Science of Sex: Sex Chromosomes Aren’t Binary

December 1st, 2019

Sex Chromosomes Aren't Binary

More than once, people have suggested that I cover biological sex in the Science of Sex feature. I have shied away from it because it seemed controversial. However, the more I know, the more I understand that some science isn’t at all controversial. In fact, understanding it can lend to our understanding of sex and gender and why it’s never been black-and-white.

One of the transphobic arguments often made is that two pairs of chromosomes determine if a person has the biological sex of a male or female: XY and XX, respectively.  Each cell contains each of these chromosomes, which each come from one of our parents. Most of us learned this in a science class, and many of us haven’t learned anything more since then.

However, there are actually more than two chromosomal possibilities, including

  • XX
  • XY
  • X
  • XXY and XXXY
  • XXX, XXXX, XXXXX
  • XYY
  • XX with translocation (XX male)
  • XY with deletion (Swyer syndrome)

With this in mind, sex seems much more of a spectrum than a binary.

Some of these variations have their own names. For example, a single X chromosome is Turner Syndrome, which is accompanied by several abnormal growth patterns. On the other hand, having three or more X chromosomes is labeled Triple-X syndrome or trisomy X, and these people have the nickname “super-female”. A “super-male,” on the other hand,  has an extra Y chromosome and will tend to be quite tall with extra testosterone. A person with Triple-X syndrome may be slightly taller and thinner than the typical XX woman, but may not be noticeably different. An assumed male who inherits an extra X chromosome or two has Klinefelter syndrome and may have stereotypically female traits and be unable to reproduce.

The latter two examples represent instances in which person’s sexual organs do not align with their karyotype. For example, a person may have the “male” sex chromosomes with female reproductive organs, which are typically not functional. This is known as Swyer syndrome/XY gonadal dysgenesis. These people are usually raised and treated as women while the counterpart is an XX “male,” who is viewed by the world as a boy. Those with this syndrome may not have a detectable SRY gene, which is responsible for an embryo turning male.

Discrepancies between chromosomes and genitals is sometimes known as being “intersex.” This term can also refer more broadly to anyone whose sexual anatomy doesn’t align with the binary (male or female) or whose internal and external genitals do not match. In the past, this has been confused hermaphroditism; however, many prefer the term “intersex” as a less offensive alternative. The World Health Organization explains how true hermaphroditism occurs when a person has mature testicle and ovary tissues. The term “intersex” is not accepted by everyone, however, because of the implication that something is wrong with someone who has these chromosomal differences.

Surgical interventions can be used on young children to “correct” these things, and those children may never realize that they do not conform to the binary. However, these surgeries. which are intended to allow a person to live normally and prevent or reduce psychosocial outcomes may not work as intended. Many surgeries were performed to feminize an intersex person, but this can affect adult sexual function. Furthermore, people may continue to develop with more typical male patterns.

And sometimes that discrepancy can exist but a person with XX chromosomes can have functional sperm while a person with XY chromosomes may have functional ovaries. So it’s possible for a person not to realize that there is a discrepancy if their sex organs are functional — to be “invisibly” intersex. While current estimates vary — some put the intersex population at about 1 out of 100 people in the US and others at 1 in 2000 — the real number could be higher because of these people.

The final nail in the coffin about chromosomes defining sex and, by association, gender, as binary might be the fact that it doesn’t take into consideration at all the role of hormones, which may not respond as expected, either. A person with XY chromosomes who has androgen sensitivity syndrome will develop female-typical sex organs because their body doesn’t respond to androgens, for instance.

There are cases of female-typical bodies and chromosomes responding in male-typical ways in limited situations. And people with similar chromosomes or bodies can still respond uniquely to different hormones and systems. Understanding these very specific differences has revealed the myriad ways that the sex binary fails us and the important things we must note to provide adequate medical care.

This messiness indicates why viewing male and female as the only two sex options is limiting and confusing. While simplifying these ideas has been helpful in some instances, it has been harmful in others. It’s not scientifically sound and can lead to social stigma for those people who do not fit within the binary.

This is all pretty basic stuff that has been researched, even if the general public hasn’t learned about it. When contrasted with gender identities, which have been conflated with sex and similarly viewed as binary, we see that there should be a lot more room for expression. It may very well be that there is overlap with people whose biology falls more toward the middle and those who identify as nonbinary or transgender (at least one study finds that the brains of trans kids match their gender identity). But these things aren’t mutually inclusive.

Further Reading

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Categories: Science of Sex

Science of Sex: What’s New In Sex Research (Summer 2019 Edition)

August 31st, 2019

What’s New In Sex Research (Summer 2019 Edition)

While I prefer for each entry in the Science of Sex archive to be a deeper dive into a specific topic, I’ll be taking a break from that this month. There’s simply so many articles that have recently come across my dashboard that I want to write about them. We’re always expanding our knowledge about sexuality, gender, and related topics, but this summer ushered in a flurry of news that really exemplifies this. It’s so exciting!

Let’s jump in. Note that relevant links are included in each section and not at the end of this post per usual.

The most recent of those articles is one about how genetics can explain same-sex behavior. Researchers concluded that there is no one “gay gene” but that several genes do connect with homosexual behavior. Furthermore, gay men and women (presumably cisgender) are affected by different genes. The survey has a few week spots including focusing on behavior versus attraction, but it’s fascinating nonetheless.

Another discovery that’s gotten a lot of media attention is how scientists isolated a gene that, when activated, would create sperm that resulted in male offspring. They successfully applied this to the sperm of mice to produce a higher ratio of male offspring than usual. They believe this applies to all mammals.

In a positive turn for preventing HIV transmission, one studies found that repeated exposure to semen can change vaginal tissues and actually make a ciswoman less susceptible to contracting the virus.

And in other STI news, there could be a chlamydia vaccine on the way! A study of the effect of the drugs on people has been found to be safe. This is good news for the 100+ million people who contract the STI globally each year.

A team looked into why men send dick pics, finding that men who do tend to be more narcissistic.  However, they determined that “he unsolicited dick pic phenomenon cannot be viewed solely as a sexist campaign, nor as a positive outlet for sexuality; instead, cases must be considered on an individual basis.”

After surveying over 2,000 polyamorous people, researchers discovered they were less likely to be religious and more likely to support political third parties. While poly folks were more likely to be nonbinary or bisexual and pansexual, they were not more likely to be gay or lesbian than monogamous people. Poly people were also more likely to make less than $40,000 annually. Research Justin Lehmiller states that,

While our results do not come from representative samples, they suggest that the stereotype of polyamorists as young, White, wealthy liberals doesn’t necessarily match up with reality. Indeed, compared to monogamists, polyamorists were not any younger, Whiter, wealthier, or more likely to identify with the Democratic party.

Surprisingly, women who were married multiple times have more surviving offspring than men who do found researchers after analyzing data about the community of Pimbwe in Tanzania.  This seemingly contradicts the idea that men achieve greater reproductive success by having a variety of partners.

According to his recently released book, ADHD After Darker, Dr. Ari Tuckman has found that a woman who has ADHD have sex 25% more often than when the man in a couple has ADHD due to ADHD’s correlation with sexual eagerness. This can lead to greater sexual satisfaction than when the man has ADHD and this leads to a great discrepancy in sex drive.

Finally, one last study finds that women who take hormone replacement therapy for menopause relief have an increased risk of breast cancer, even more than a decade after they cease the medication. The longer a woman is on HRT, the greater her risk for breast cancer. This is potentially concerning as estrogen and other hormones have been prescribed to help women cope with the symptoms of menopause and to enable them to continue enjoying sex. There was not a similar risk for women who were obese, however.

 

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Categories: Science of Sex

Science of Sex: Finger Length and Sexual Orientation (The 2D:4D Ratio)

December 22nd, 2018

More than fifteen years ago, when I was still in high school, I had heard there was something about your hand shape that could be linked to being gay. I’d heard this repeated throughout the years but always in a way that indicated it was an urban legend, simply a myth. Why did I think this way? Because no one discussed the science; they just held up their hands and explained this fact.

This month’s Science of Sex explains the theories about why hand shape and, specifically, finger length correlates with gay orientations. I hope you enjoy learning a little more about physical and sexual development if you, too, had heard about this phenomenon before and had wondered whether it was true or how.

Science of sex finger length orientation 2d:4d ratio

Researcher Jonathon Manning was the first to notice a correlation between finger length and homosexuality in men. He wrote about how men having a ring finger that’s longer than an index finger (rather than the index finger being longer or both fingers being the same length) can be an indicator of sexual orientation. This high ratio (greater than 1), known as the 2D:4D ratio, is typically more common in women than in men.

But there are a few caveats.

First, we’re talking about the right hand specifically. Secondly, measurements should be taken from the crease to best compare overall finger length. Third, to reiterate, the high ratio is already prevalent in women, so this measurement applies less to them (although, you’ll discover that it does highlight some interesting traits).

This doesn’t mean that you should assume you’re gay if your ring finger is longer, but it might be an indication of biology at play if you don’t identify as straight.

Why does this happen? Researchers know that hormones such as testosterone and estrogen affect our development in the womb. A longer ring finger is connected to the influence of testosterone (a type of androgen) in utero. A lower ratio, which is typical of straight men, corresponds to greater testosterone influence in the womb. The interplay between testosterone and estrogen during this stage is also important.

You might remember that testosterone which encourages skeletal growth. This is why men tend to be taller and have defined Adam’s apples; testosterone spurts during puberty cause this. But finger length is visible at birth, unlike changes that don’t occur until puberty.

Finger length is just one thing that can be affected by hormones in utero. Research suggests, that on average, a gay man’s brain is a bit more feminized than a straight man’s, and that a gay woman’s brain tend to be a bit more masculinized. Of course, there is great variety not just between the sexes but in a single sex, so it is not accurate to say that a game man has the brain of a straight woman. You have to consider the spectrum.

However, there are other ways in which gay men and women are more similar to straight women and men, respectively. Gay men and straight women tend to do better when it comes to verbal measures, and gay men are also more similar to women when it comes to being dependent on landmarks, not direction, when navigation or providing directions. Young gay boys even gravitate toward individual sports rather than team sports.

Higher exam scores, increased neuroticism, better visual recall (in women), and improved literacy also correlates with a greater testosterone influence in utero. There are also some risks from increased testosterone exposure, including an increased risk of prostate cancer as well as lower sperm count, increased risk of heart disease and obesity (in men), and increased risk of mental health conditions such as anxiety, depression, alcohol dependence, and bulimia.

Many of these differences exist even in children; although, some people wonder whether children who are more ‘sex typical’ who later identify as gay may trace their sexual roots more to childhood events than fetal development.

The potential differences and risks I’ve listed above occur to a high 2D:4D ratio. But it’s not just the high ratio that matters. Bisexual men, for instance, have a lower ratio than gay men. Lesbians also tend to have a lower digit ratio, indicating a decreased preference for a masculinized partner, than straight women. However, a high ratio in women correlates to identifying as femme rather than butch.

Amazingly, scientists have been able to study women who were identical twins where one was gay, and the other was not. The differences persist.

A low digit ratio even corresponds with an interest in polygamy.

This research indicates not just the biological differences between gay, straight and bisexual people, but also the significant impact of hormones during our fetal development. The more I read about this, the more I realize that a ton of research supports these theories.

However, I would love to see more research on bisexual men and women specifically — not just because I am one.

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Categories: Science of Sex

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

My G-Spot Makes Me Cry

February 24th, 2017

Well, there you go with a sensational title. Sorry that the rest of this post will be logical and reasonable (sorry not sorry).

So the last time I masturbated (with a unicorn dildo, no less. It was pretty awesome), was the first time I’d experienced penetration in a while. A while might be quite the underwhelming way to describe it, in fact.

Regardless, it was the first time. And my body stretched and groaned against it, but it all worked out swimmingly. I enjoyed new toys and a few orgasms, and I squirted for the first time in (don’t say “a while”).. you-don’t-what-to-know-how-long.

It was altogether a pleasing experience if it was slightly less than toe-curling, but it was also followed/joined by an onslaught of tears. I posted about it on Twitter — briefly.

And discovered that I’m not alone, but I can only tell my story.

There’s a lot of hokey new-agey type stuff about the G-spot, but it certainly seems a quick button for catharsis. I’m certain it’s rooted in biology, and oxytocin specifically causes all sorts of emotions when it rushes through your veins.

But I temporarily forgot this. There wasn’t any way for me to be contained. I was both squirting and crying, and if this sounds like a bad thing.. it’s not. It was a cathartic cry like when you watch a chick flick, perhaps with ice cream, and just let it go.

It was primal and unedited and perhaps just what I needed. It was unexpected only because it’s inconsistent. But hindsight is 20/20, and why wouldn’t I have an intense reaction the first time I experience penetration in months?

And it’s not at all like crying and masturbation or sex don’t go hand in hand for me. When I was with my ex, I discovered that I would sometimes cry from sex. It was because of overwhelming feelings of love and connection, but it pushed the experience to an intensity that I desired. With more recent partners, I’ve achieved a similar intensity through rougher sex.

After I stopped having sex with The Bartender, my poor broken heart was unable to think of anything else when I jacked off, and this resulted in all sorts of crying as I came. It wasn’t pretty, that’s for sure, and it wasn’t always wanted. But it ushered in all sorts of feeling, and sex is one of the few times when I am relaxed enough, stripped bare enough and out of my head enough to just feel. To be.

It’s more difficult, of course, if I’m dealing with unresolved feelings in addition to hormones. Although, that wasn’t the case this time around. I was in a place where I could just notice and feel both amused and impressed with my physiology. It’s a pretty neat thing.

Sometimes my G-spot makes me cry, and that’s always okay even if it’s inconvenient.

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Categories: Masturbation

I’m PMSing

August 19th, 2010

This is exciting news. Except for everything that goes with the upcoming menstrual flow. But, you see, I’ve never been in a place where I was happy enough to even recognize PMS so being able to do so is kind of awesome in its own way. Plus, even though I’m not there yet, recognizing the emotional and mental symptoms gives me hope that I may be getting to know my boy a bit better. I really like the idea that my body may not always be a stranger whose boobs I love but whose signals are never loud enough to understand. Who ever thought I’d be happy about PMS?!

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Categories: Everything Else

Image © MisterUnlucky; used with permission.