Science of Sex: Marijuana and Sexual Activity

November 30th, 2017

Welcome to the sixth installment in a new feature on Of Sex and Love: Science of Sex. In this feature, I plan to discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.

I try to update Science of Sex every second Saturday of the month, so check back soon.  This month’s incredibly late Science of Sex post is a departure from previous posts, but it’s one that I hope you will enjoy.

science of sex marijuana

A few studies have compared how substances affect sex drive, performance, and satisfaction. The two most commonly researched substances are alcohol and marijuana, with studies on the latter becoming more common as marijuana continues to be legalized. These studies piqued my interest!

Thus far, studies on cannabis use and sex point to some similarities to alcohol: people generally feel more relaxed and attractive when they mix either substance with sex.

Many people report being more aroused when drunk or stoned, but there’s a surprising difference between men: 50% of women reported being more aroused after smoking pot compared to 39% of men. The reasons may not bee entirely due to a chemical difference, however. Researchers suggested that women were more likely to need a reason to allow themselves to have sex, and marijuana changes the “path” to sex with which women are more concerned than men.

Cannabis use can decrease a man’s plasma testosterone (women see an opposite effect, which might account for the greater increase in desire) with greater effects on more heavy smokers. This is especially true on days after intense use. Thus, marijuana can both increase and decrease desire in men. Sperm counts also drop in these men to below 30 million per ml, which could be an obstacle for people who are trying to conceive.

Regardless of those differences, both men and women who smoke pot are likely to have more sex than those who don’t — about 20% more sex. No conclusions have been drawn, but the combination of increased arousal and decreased inhibition probably helps.

Smoking more marijuana doesn’t necessarily lead to even more desire, however. One joint seems to be the sweet spot. Doubling that still increases desire but only by half as much.

Discover how the dual-control model of sexual desire affects arousal, too.

Interestingly enough, both alcohol and marijuana affect how people choose sexual partners, but someone is more likely to sleep with a friend when stoned and a stranger while drunk. Regrets are increased after drunken sex more than stoned sex, too. Marijuana does lead to increased risky behaviors, such as not using condoms with established partners.

Most people are familiar with the phenomenon known as “whiskey dick,” which occurs when a man who has imbibed alcohol cannot become erect. Some men experience difficulty with erection while high, but not nearly as many.

The influence of marijuana on orgasm is varied:

  • Some people experience more orgasms
  • Some have more intense orgasms
  • Some have fewer orgasms or difficulty orgasming

The mind that marijuana puts someone in can prove too much of a distraction and may come with paranoia or other negative side effects that do not bode well for sex.

The type of sex that people have after smoking tends to be softer and gentler while people who drink have more aggressive sex. The sex is also likely to be slower, and many men report lasting longer after smoking, likely due to the endocannabinoid system.

At least one study finds an increased likelihood of sex during menstruation when marijuana is involved. Mixing cannabis and pregnancy may have unwanted effects. Research suggests that marijuana both reduces conception and successful pregnancies.

Pot might be a moon for desire more often than not, but there are definitely times when you should abstain, and users should beware the increased potential for risky behaviors.

Further Reading

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Science of Sex: HIV and AIDS

October 24th, 2017

Welcome to the seventh installment of a feature on Of Sex and Love that I call Science of Sex. In this feature, I discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.

I update Science of Sex every second Saturday of the month — except for this one thanks to issues with connection, computers, and inspiration. Better late than never! 

Science of Sex HIV and AIDS

We’ll dive right in. I assume you all know that HIV, Human Immunodeficiency Virus, is a sexually transmitted infection that compromises the immune system by destroying CD4 T-cells. When it progresses to the most advanced stage, we refer to it as Acquired Immune Deficiency Syndrome or AIDS. In the final stage of HIV, the immune system has become too compromised to fight off HIV or other infections and illnesses (including pulmonary tuberculosis,  and recurrent pneumonia), which will take advantage of this time to infect the person. Treating the virus can put off progression to this final stage.

When HIV and AIDS first came on the scene in 1981, it was a death sentence. Within the first year, around half of the American men who were diagnosed with HIV died. There is much I could say about the cultural impact, especially because HIV/AIDS affected homosexual and bisexual (as well as their female partners), the most. We’re all familiar with the endemic and the ensuing panic that arose after the discovery of HIV.

While the infection remains an epidemic in some areas, including Cameroon and the Democratic Republic of Congo, where the infection originated, our understanding of HIV and AIDS has greatly increased over the last three and a half decades.

For example, promising tests of a new antibody in primates indicate that it is capable of preventing contraction of 99% of HIV strains. Testing on humans should begin next year. This is good news, but getting there was a difficult process for several reasons.

One of the main reasons that tackling HIV is difficult is becaise there are different types and subtypes of HIV. When most people speak of HIV, they mean HIV-1, which is the most common in the United States and the UK, among other locales. 95% of all HIV cases are HIV-1, but HIV-2 remains common in western Africa but has spread to other countries, and it’s even possible to contract a hybrid of the two strains.

Doctors have had the most success treating HIV-1, which is better understood. HIV-2 doesn’t respond to all of the treatments that HIV-1 responds to. It is less likely to develop into AIDS. People with HIV-2 are less likely to be diagnosed or to receive treatment for the virus, however. Originally, most HIV tests looked for HIV-1 antibodies, but modern tests search for signs of both types of HIV.

I’ll focus on HIV-1 from here because that’s what we know the most about and where we’ve made the most progress. HIV-1 presents challenges because there are 4 groups: M, N, O, and P. The majority of people in the M group have subtype B; although, subtypes A, C, D, F, G, H, J, and K exist as well as 89 hybrid viruses or ‘circulating recombinant forms’. Cameroon still has the widest variations of strains. Just like more research is needed into the other groups and the less common subtypes of group B, including CRFs,

There is good news when it comes to treatment, however. Because HIV is a retrovirus, researchers have designed antiretroviral therapies (ART), to treat people with HIV and also sexual assault victims who may have been exposed (official CDC guidelines recommend ART for high-risk victims). The first ART took six years to develop and approve, but there are now six categories:

  1. Entry Inhibitors work by stopping HIV entry into CD4+ cells
  2. Nucleoside Reverse Transcriptase Inhibitors, also known as nukes or NRTIs, help to block the reverse transcriptase proteins that HIV needs to multiply
  3. Non-Nucleoside Reverse Transcriptase Inhibitors, also known as non-nukes or NNRTIs, work by binding to and disabling the reverse transcriptase proteins that HIV needs to multiply
  4. Integrase Inhibitors block the enzyme that HIV needs to infect CD4+ cells with its genetic material
  5. Protease Inhibitors, also known as PIs, inhibit an enzyme that HIV needs to make copies of itself

When a doctor prescribes a combination of three ARTs from two different categories, it’s known as highly active antiretroviral therapy (HAART).

Between 2008 and 2014, new HIV infections dropped 18% in the United States with the biggest drops in drug users and heterosexuals. We lack research into HIV transmission rates for victims of sexual assault and sex workers. The data have is dated (around 1% of sexual assault survivors were tested for HIV in 1998, and half of them tested positive, presumably because they fell into the high-risk group. Furthermore, sex workers are ten times as likely to contract HIV, and approximately 12% of sex workers have the infection.), and change hasn’t been tracked. Hopefully, transmission rates have dropped for those groups as well.

The progress that has been made not only improves quality and length of life but reduces the risk of spreading HIV to new partners. The CDC has recently updated its HIV/AIDS guidelines for the first time since 1990. The updated guidelines finally indicate that the risk of spreading HIV-1 to sexual partners, to fetuses or infants via breastfeeding is virtually none as long as the person with HIV takes a daily HAART treatment. Mixed-status couples can safely try to conceive without worrying about the risk of HIV contraction.

While this has been one of the longer Science of Sex posts, it was one of the most fascinating to research. I knew very little about HIV/AIDS when I began, and encourage you to go through the extensive list of resources below if you want to know more about HIV.

Further Reading

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Science of Sex: Pheromones

September 9th, 2017

Welcome to the sixth installment in a new feature on Of Sex and Love: Science of Sex. In this feature, I plan to discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.

Enjoy!

science of sex pheromones

You probably think of pheromones as sex chemicals. Many animals produce pheromones, chemicals that help attract mates among other things. But plants and bacteria also produce pheromones that serve various purposes. These chemicals are emitted through sweat, saliva, and other glands.

Human infants, for example, may detect pheromones that lead them to their mothers’ breasts, which is necessary for nursing. One type of moth releases a pheromone-filled mucus cocktail to attract potential suitors. Pheromones may signal whether another member of the same species is healthy and thus a good potential mate. Queen bees attract drones with pheromones (and unappealing pheromones may even serve as a pest repellant). Nature has plenty of examples of pheromones.

It’s the nose that detects pheromones in animals like humans and mice, but detection of these chemicals is unconscious. You wouldn’t realize when pheromones are at play, and animals certainly don’t.

Scientists believe pheromones in a man’s sweat can attract a woman to a man, even if the idea of smelling someone’s sweat isn’t appealing. Since the 1970s, researchers have found ties between body odor and attraction. You may already be familiar with the experiment in which women were asked to smell t-shirts covered in a man’s sweat and rate attractiveness. More recently, a study has shown that a man’s testosterone may rise when in the presence of pheromones of menstruating women.

Even exposure to pheromones from the same gender can elicit an effect as is the case with women and their menstrual cycles (and sweat from any gender can impact the menstrual cycle when applied near the nose). However, the case for pheromones in humans isn’t a strong one, and no specific chemicals have been extracted to reproduce that effect artificially.

Researchers once thought that the vomeronasal organ (VNO) is the pheromone receptor in animals. But humans have a particularly small VNO — and some have none at all. The genes that turn on the VNO aren’t active in every person, either. The VNO may be only part of the picture, too. One study showed that pigs could still detect pheromones even when the VNO duct was plugged, leading scientists to suggest that more than the VNO is necessary to detect pheromones.

The terminal nerve in the brain has been proposed as a pheromone detection, and hamsters with terminal nerve damage do not reproduce. This all makes it hard to make a solid case for human pheromones.

That doesn’t stop companies from promising you can attract a mate and make them obsessed with you with a little help from pheromones. But it does mean that the chemicals, if any, contained in these products are not human pheromones. They come from other animals, usually pigs, and there isn’t proof that they will work for you, a human person.

Even if researchers could prove that human pheromones exist and identify those chemical compounds, a true human pheromone product may not improve your sex life as much as you’d hope. For starters, you’d still produce your own pheromones. Pheromones also have to battle with all the bath and body products we use on a daily basis, which is one reason why researchers haven’t found a strong connection between pheromones and attraction in humans. Finally, humans have a host of other senses that come into play when it comes to attraction.

There’s enough evidence of pheromones in humans to warrant further investigation, but we cannot make a conclusive case for human pheromones.. yet.

Further Reading

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Science of Sex: Dual Control Model

August 13th, 2017

Welcome to the fifth installment in a new feature on Of Sex and Love: Science of Sex. In this feature, I plan to discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.

Enjoy!

dual control model of sexual desire

I’ve been interested in the dual control model since I first read about it in Emily Nagoski’s book Come As You Are, which I highly recommend but apparently never got around to reviewing. The dual control model was first proposed by Bancroft and Janssen in the early 2000s. This theory is relatively new, but it’s become accepted because it explains desire for many people.

The dual control model explains why desire is more complicated than we’ve been led to believe. It’s not just about what turns us on (our Sexual Excitation System (SES)). Turn offs (Sexual Inhibition System (SIS)) are also as important, and things that arouse you and detract from your desire happen at the same time. Whether you want to have sex is the result of this equation.

SESes (accelerators) can include being attracted to someone, sexy books, music or movies, someone who smells good and, in a few people, stress. SISes that put the kibosh on your arousal might be needing to shower or brush teeth (or needing the same from your partner), having kids or roommates home in the house, dissatisfaction with a relationship, being self-conscious about your body, or any kind of stress. Mood can be a brake, and women are more sensitive to mood when it comes to desire.

The original surveys were given to men and focused on issues with erectile dysfunction. Bancroft and Janssen divided inhibitors into type types for men: SIS1 refers to performance anxiety while SIS2 is inhibition due to possible consequences of sex. Since then, a survey with modified questions has been given to women.  Results indicated that feelings about relationships are especially important to a woman’s desire.

Nagoski’s book is geared toward women, and the dual control model is especially helpful for women who can’t figure out why they don’t want sex more — or even if that means something is wrong with them (hint: there’s not). The dual control model specifically explains why pressing down the gas pedal isn’t enough for many people to want more sex. They must let up on the brakes (inhibitors/turn offs).

I found this explanation especially intriguing because it affects everyone. Dr. Nagoski does discuss this in Come As You Are, mentioning that men tend to have more sensitive accelerators and less sensitive breaks than women. The things that want to make them have sex are many and powerful while the things that make them hesitate are fewer and weaker.

I was eager to apply the dual control model to myself. As best as I can tell, I have more sensitive accelerators than many women but more sensitive brakes than most men. I think many people will benefit from analyzing their desire though the filter of the dual control model.

Interestingly, bisexual women tend to have higher levels of desire than straight women according to the dual control model. I’d like to see how different demographics stack up to straight men and women.

Further Reading

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Science of Sex: Genetic Sexual Attraction

July 15th, 2017

Welcome to the fifth installment in a new feature on Of Sex and LoveScience of Sex. In this feature, I plan to discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.

Enjoy!

science of sex genetic sexual attraction

Genetical sexual attraction is the phenomenon where two people who are biologically related but first meet in their adulthood as strangers and experience sexual attraction to one another. Genital sexual attraction, or GSA, can occur between siblings or a child and a parent.

Adoption is the main environment of GSA, and changing laws allowed many adopted people seek out their biological families, which can lead to one or both parties experiencing genetic sexual attraction. The attraction comes on suddenly and strongly and the senses of hearing, touch and smell play a significant role. To many, the term “attraction” isn’t strong enough. It’s an obsession or an addiction with the accompanying compulsions and inability to stop thinking about their attraction.

Cause of Genetic Sexual Attraction

Part of the draw might be meeting someone who shares similar personality traits and appearance, a result of genetics. This can lead people to a frenzied state much like new relationship energy — except they’re related. There is also an argument for an attraction based on similar genes, specifically having similar phenotypes (traits an individual of a species has based on gene and environmental interaction), which would obviously be the case for two people who are related.

People who experience genetic sexual attraction often feel confused and shame as they grapple attraction for their family members. People who try to deny their thoughts and feelings may wind up even more entrenched due to the ironic process theory (your brain must keep thinking about any subject you’re trying to avoid to monitor whether it’s thinking about it). In some instances, attraction occurs for only one of the people, and that person may pursue the object of their desire compulsively.

When the attraction is equal, the parties may engage in sexual activities or intercourse. GSA sex seems to occur most frequently between siblings. Some couples have been arrested and tried for incestuous relationships. These laws strive to reduce offspring from an incestuous relationship because those children are likely to suffer severe birth defects or mental disabilities.

Some people who have developed romantic relationships with their biological family members are fighting for the right to marry the people that they have only known as an adult – and never as a family member.

There are reported cases of GSA among adults who only discovered that they were related to their romantic/sexual partners after developing a romantic/sexual relationship.

Incest Taboo

It might be more telling to understand where the taboo incest comes one. It may be due to the Westermarck effect,  also known as reverse sexual imprinting, which endeavors to explain the incest taboo by showing that people develop a sort of sexual immunity to their family members after living with or near them during their developing years.

Dr. Maurice Greenberg performed a study in 1992 and discovered that many people who experienced genetic sexual attraction to a biological family member shared typical disgust toward incestuous relationships with their adopted families, which led him to differentiate between incest and GSA.

However, we also know that sexual imprinting (in which someone chooses a mate similar to a parent) exists and can occur in adoptive families as well as biological ones.

Frequency of GSA

One study suggests that it happens in as many of half of those instances of adult family members meeting for the first time while another study found that every informant had experienced genetic sexual attraction and one-third of those people had engaged in sex with a bio family member.

A few professionals and communities have developed to provide support to those people who might be struggling, either because they’re experiencing unwanted GSA or because they’ve chosen a relationship with a biological family member.

One notable name is Barbara Gonyo, the woman who first coined the term genetic sexual attraction after herself experiencing it toward her son. While he didn’t return the attract and Gonyo eventually moved on from her obsession and now provides counseling services to others like her.

Like any attraction, the flame can wither and die. Barbara has been able to overcome the feelings of attraction to her son, who is now married.

Further Reading

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Science of Sex: HPV and the HPV Vaccines

June 17th, 2017

Welcome to the fourth installment in a new feature on Of Sex and Love: Science of Sex. In this feature, I plan to discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.

Enjoy!

Science of Sex HPV

Human Papilloma Virus in a Nutshell

HPV is the virus that causes genital warts, but just because you don’t have any symptoms doesn’t mean you don’t have HPV. It’s one of the most common sexually-transmitted infections with over 200 strains (strains 16 and 18 cause over two-thirds of all cervical cancer while low-risk strains 6 and 11 cause most warts). Over 80 million people or about 1 in 4 people have it. It’s easy to transmit through skin-to-skin contact, so even using condoms may not prevent HPV. The CDC advises that ‘nearly all’ men and women will contract HPV in your life, and it’s likely that many people don’t even know they have it.

HPV doesn’t just cause warts. It can lead to irregular PAP smear results for women and cause cervical cancer (HPV can also be the culprit for other cancers, including that of the throat and anus). Those results can lead to a woman getting tested for HPV, but there is currently no test for HPV in men who have an asymptomatic strain (some sources indicate that a test does exist but it’s expensive and invasive).

Treatment of HPV may mean doing nothing at all. Most cases clear up within two years, but this isn’t always the case.

The HPV Vaccine

A vaccine for several of the most common strains of HPV, including some that cause cervical cancer, Gardasil, became available about 10 years ago. There are now three different vaccines for HPV available (Cervarix, quadrivalent Gardasil, and 9-valent Gardasil-9), the latter of which cover more strains of HPV than the original. One study concludes that HPV vaccines can prevent “most” invasive cervical cancers (around 70% of cervical cancer for the 9-valent vaccine and 66% for original Gardasil) as well as some oral cavity, penile, laryngeal and vulvar cancers. These vaccines are at least 90% effective at blocking those strains.

The vaccines consist of three doses that you can take between ages of  11 and 27 (for women) or 21 (for men). Younger patients may only need two doses. Even if you can’t take all shots within this time frame, you’ll still benefit from at least one dose. Similarly, the vaccine is still beneficial if you’ve already become sexually active, but it’s more beneficial if administered before sexual activity. In this case, the younger the better.

Although at first recommended for girls, HPV vaccines are beneficial for boys who can contract and transmit HPV. But it’s less likely that a male will no if he’s HPV-positive, which means he’s more likely to transmit it to a partner.

Still, fewer boys than girls are being vaccinated (12% of boys had received all three doses compared to 36% of girls in 2013), and vaccination occurs at a later age. Fortunately, vaccination rates have increased through the years, perhaps as no serious side effects have arisen over the years and the efficacy of the vaccines have been proven. For girls, infections by strains of HPV that the vaccine prevents has dropped 64% since 2006.

Let’s hope that vaccination rates rise, gaps close and strides can be made to cover more strains of HPV in future vaccines!

Further Reading

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Science of Sex: Birth Control

May 13th, 2017

Welcome to the third installment in a new feature on Of Sex and Love: Science of Sex. In this feature, I plan to discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.

Enjoy!

science of sex birth control

Barrier methods of birth control, including condoms, cervical caps, diaphragms and the sponge block sperm from moving through the cervix to the uterus, where it would otherwise fertilize an egg. If the barrier becomes compromised, say, by a pinhole or friction, it’s less effective.

Barrier methods are sometimes combined with spermicide in the form of nonoxynol-9. As I mentioned in my previous Science of Sex post on lube, nonoxynol-9 is detrimental to sperm, but it can also have a caustic effect on your sensitive vaginal tissues and can even make it more likely to contract an STI.

Hormonal birth control varies, however. The regular birth control pill, which contains a combination of both estrogen and progestin, a synthetic form of progesterone.

During a woman’s menstrual cycle, estrogen peaks, signaling for her pituitary gland to release other hormones (follicle stimulating hormone and luteinizing hormone, to be specific). This leads to the release of an adult egg, which can be fertilized if sperm makes its way to the egg.

When a woman is on combination birth control, the hormones create a balance and that estrogen spike is prevented from occurring, so no egg is released. Progestin also makes a woman’s uterine lining less ideal for hosting a fertilized egg. Other hormonal birth control methods, including the patch and NuvaRing, work in a similar way.

However, not every form of hormonal birth control contains a combination of hormones. The progestin-only pill (called a POP or mini-pill) lacks estrogen as the name suggests. These pills are less effective than combination birth control. Because they have no estrogen, these forms of birth control may allow more breakthrough bleeding than combination birth control.

Progestin-only birth control may be prescribed to women who are breastfeeding (breastfeeding naturally prevents ovulation, but the mini-pill in addition to breastfeeding is more effective than breastfeeding alone) as well as those who suffer from migraines. Combination pills were once believed to contribute to migraine headaches; however, more recent science suggests that this may not be the case and that combination BC may even help prevent migraines. Nevertheless, taking combination birth control if you already experience migraines with auras might contribute toward strokes.

The Mirena and Skyla IUDs (in the form of levonorgestrel), Implanon, and Depo-Provera are progestin-only BC methods.

Most birth control falls into the category of barrier or hormonal methods, but copper IUDs alone take a different route. Copper IUDs (Paragard in the US) are sometimes known as just a copper-T or coil and work by releasing small amounts of copper into your blood stream. Copper is an effective spermicide without the side effects of nonoxynol-9, damaging sperm so to prevent fertilization. Copper IUDs may also prevent ovulation.

Further Reading

Did you enjoy the second installment of Science of Sex? Do you have further questions or suggestions for next month’s subject? Leave me a comment!

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