Science of Sex

Science of Sex is a monthly feature on Of Sex and Love in which I discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader.

I end with some extended reading material for people who want to know more about the subject of each post.

Previous topics include the dual-control model of sexual arousal, pheromones, the women of sexology, and habituation of sexual arousal. Find the entire archive below.

Check back every second Saturday for a new sexy science post.

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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Categories: Science of Sex

Science of Sex: Lube

April 11th, 2017

Welcome to the second 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 lube

I am not the first person to write about lube, and I doubt I’ll be the most effective. But lube is so interesting from a scientific viewpoint, and I believe we can never talk about it enough.

Lube should make sex better, but it doesn’t always. For example, lubes that contain the spermicide nonoxynol are quite abrasive to sensitive tissues, resulting in micro-tears that actually facilitate the transfer of infections. Multiple studies have shown that Nonoxynol-9 contributes to HIV transmission.

Osmolality

Depending upon its osmolality, the measurement of particles per KG in a solution, lube may be doing unseen damage to your vagina or anus that increases the likelihood of an infection, too. Many lubes have a much higher osmolality (greater than 1,000 mOsm/Kg) than the vagina (~275 mOsm/Kg) or anus meaning there are more particles in the lube than the tissue it comes in contact with.

Osmolality is also important when it comes to sperm, which have a different measurement than vaginas, anuses, saliva and many lubes. By default, nearly all lube proves to be an inhibitor to sperm, so you’ll want to look for sperm-friendly lube when it comes to TTC.

Lube pH

If your lube has a pH that differs from your body’s natural pH (between 4.5 and 7 for most vaginas; pH varies during your cycle and life), you might find yourself dealing with a yeast infection while your body seeks balance.

Other Problematic Ingredients

And personal lubes that contain L-arginine, which is typically used to encourage sensitivity and arousal, can cause a herpes breakout. Sensation lubes (warming or cooling) typically rely on menthol or capsaicin to produce the desired effect, and every body responds to these chemicals differently.

Numbing agents such as lidocaine or benzocaine are sometimes found in anal lubricants. However, experts recommend against numbing the area because it both reduces pleasure and makes it harder to tell if you’re being too rough, which could lead to damage.

Lube and Your Toys

Even if lube is good for your body, it may not be compatible with your toys, which is the case with low-quality silicone lube and silicone toys. Using them together can cause an interaction that increases the porosity of your silicone toys, so they’re not as body-safe as they once were.

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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Categories: Science of Sex

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Science of Sex: Conditioning

March 11th, 2017

Welcome to the first post 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 hope you enjoy. 

Science of Sex -- Conditioning

We all learned about Pavlov, his dogs and classical conditioning in school. By associating a neutral stimulus (the ringing of a bell) with a desired reward (food), Pavlov was eventually able to condition dogs to salivate at only the sound of the bell, even when there was no food in sight.

Much like food conditioning, sexual conditioning exists. However, many people first stumble across their capacity for conditioning quite by accident. Whether you masturbate to hardcore porn during your formative years and become unable to get off any other way or you realize that you’re physically turned on at the sight of a bright red lipstick that your partner wears specifically for sex, you’ve been conditioned.

Human’s aren’t the only animals capable of sexual conditioning. In fact, humans may be less prone to this type of conditioning than other animals. People who higher sex drives who more easily respond to sexual stimuli are the most likely candidates to become sexually conditioned, whether by accident or design. Most studies focus on men, who may be more likely to become sexually conditioned; however, women can experience it, too.

Upon discovering sexual conditioning, some people like to experiment it. BDSM practitioners sometimes employ sexual condition as it’s especially helpful to force someone to orgasm on command. You can certainly play around with sexual conditioning without being kinky, however.

Attempting to sexually condition someone without their knowledge may cross fall into consensual gray area. And classical conditioning has been used for nefarious purposes: specifically to change a person’s sexual orientation. The process, known as conversion therapy, attempts to change a person’s orientation with stimuli such as electricity or nausea drugs. No reputable studies show that this type of conditioning is successful, and one proponent of conversation therapy who wrote a controversial paper about it has since changed his stance and offered an apology to the gay community.

Finally, PTSD because of past trauma can lead to conditioned behavior in otherwise neutral environments because of fear conditioning. This is one reason why it can be difficult for survivors of assault to engage intimate behavior after the assault.

Fortunately, negative conditioning and fear conditioning may be reversed through a process known as counter-conditioning.

Although classic conditioning used for sexual purposes is possible and can be fun, we must address the ethical implications as well as the limitations of sexual conditioning.

Further reading on conditioning and sexuality:

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

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Categories: Science of Sex

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