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Why Are Girls Entering Puberty Earlier?

Teen girl (Barnorama)

It might seem like teenage girls are looking younger and younger each year, but there’s some truth to that. Researchers are finding that the age of onset puberty has been declining over the years, and girls are beginning to physically resemble grown women at younger ages.

A 2010 study put out by “Pediatrics,” the American Academy of Pediatrics’ (AAP) journal, followed a cohort of 1.2K+ girls between the ages of six and eight years of age from New York, Cincinnati and San Francisco. The study measured breast “budding,” normally the first physical step in female puberty. The results found that girls were beginning this stage around ages seven or eight, which is earlier than girls who were born only 10 years ago. (Incidentally, there was no change in age of first menstruation.)

This is even earlier than what was found in a previous AAP study completed in 1997. That year, results showed that girls began puberty between eight and nine years of age.

So what’s been causing the change? There appears to be a link between sugary drinks and early onset puberty for girls. The study defined early puberty as age of first menstruation, but not by breast budding.

It appears more research is needed, but this is an issue that needs to be addressed sooner rather than later.

How Many People Identify as Asexual?

AVEN Logo (Asexuality.org)

Along the spectrum of sexuality sits asexuality. (Actually for Alfred Kinsey, he put the concept outside his famous Kinsey Scale, marking it with an “X.”) Those who identify as asexual do not feel sexual desire and/or want sexual intercourse (though they may still have romantic feelings).

Asexuality and its nuances have been misunderstood for decades, as have those who self-identify with the term. So how many people identify as asexual?

It’s hard to say. Like many sexual statistics, it’s all self-reported. But there have been a few studies done.

Kinsey estimated that asexuals numbered around 1.5% of the adult male population in the later 1940s to early 1950s. But he didn’t mention female asexuals, and we don’t know how thorough his methodology was.

Elsewhere, a 2004 British study analyzed data and found that around 1.1% of Brits claimed the label. A recent article on “Wired” named estimates ranging from .6% to 5.5%.

There’s no definitive way to tell. But hopefully more data will be uncovered as research into asexuality grows.

How Common Are Hermaphroditic Goats?

Hermaphrodite goat (NPR)

A recent NPR article on a hermaphroditic goat in Gaza spawned the topic for today’s blog post. The article gave this intriguing stat:

When two naturally hornless goats breed, around 1 in 5 offspring is a hermaphrodite.

I decided to look around to see if that was true. NPR didn’t hyperlink or otherwise cite their source, so I had to go at it myself.

The best thing I found was also the oldest: a 1944 study on the relationship between hornless goats (called “polled” in this case) and subsequent hermaphroditic traits. Spanning 20 years, the study examined the various couplings between polled and horned goats. It found that the horns were a recessive (weak) trait, and that 25% of goat offspring from two dissimilar goat partners (one polled and one horned, in this case) would be likely to be hermaphrodites. The study also found that goats that possessed both horns and hermaphroditic traits were rare.

Isn’t it fascinating how diverse nature is?

Do Musicians Get Laid More?

ACDC’s Malcolm Young, 1970s (ACDC)

Happy Friday! We’ve all heard that musicians get laid more than the average dude with no guitar skills. (Well, not just guitar, substitute any instrument here that you prefer.) It’s thought of as a evolutionary differentiator to allow potential partners to pick them on the basis that they’d be a good mate for life, or for just one night.

But is this true?

It turns out that this might not be the case. A recent study, published in “Evolution and Human Behavior,” surveyed 10K+ Swedish twins ages 27-54, both women and men, to determine this dilemma. The study examined benchmarks such as the age each person first had sex, number of sex partners reported and the number of kids they had.

Here’s what the study ultimately found:

Contrary to predictions, the majority of phenotypic associations between musical ability and music achievement with mating success were nonsignificant or significant in the other direction, with those with greater musical ability scoring lower on the measures of mating success.

Looks like every musician you crushed on in high school had some other stuff going on that you found attractive. Because it wasn’t evidently just that guitar.

The results follow two earlier Swedish studies that found that music doesn’t hold enough weight as a desirable-mate signifier to definitively say that the trait/skill alone attracts mates.

So if you’re debating treating yourself to music lessons after that hard-earned promotion, and if you’re looking for partners (short- or long-term), you might want to skip the lessons and just use that promotion as a talking point.

What are Common Personality Traits of Women Who’ve Read the “Fifty Shades of Grey” Trilogy?

‘Fifty Shades of Grey’ still (The Tipsy Verse)

Now that we’ve all seen “Fifty Shades of Grey” (or are waiting for Netflix/Redbox/not-so-legal means), we can all relax until the franchise’s next installment comes out.

Until then, you have time to catch up on the rest of the trilogy. But that might say certain things about your personality.

Last year, Michigan State University researchers found that women who had read the erotic trilogy were “more likely to have a verbally abusive partner with stalker traits and eating disorders than non-readers.” The study polled 655 women ages 18-24, and was published in the “Journal of Women’s Health.” The subjects were divided into thirds of non-readers (those who hadn’t read any of the books), one-book readers (those who’d only read the first book) and three-book readers (those who’d read the entire trilogy).

Compared to women who hadn’t read the books, women who had read them reported more abusive behavior in relationships: They were 25% more likely to have been yelled at by a partner, and 34% more likely to have had a potential stalker.

But it’s unclear whether the subjects engaged in this behavior before reading the books, so we can’t say definitively that the books influenced them.

How Many People Experience Same-Sex Attraction (SSA)?

TLC’s ‘My Husband’s Not Gay’ (Salon)

With TLC’s special “My Husband’s Not Gay” premiering recently, same-sex attraction (SSA) has come to the forefront of discussion in sexuality. SSA is just what it sounds like: a person is attracted to someone of the same gender, or sex. However, someone with SSA may or may not act on the attraction, and may or may not identify as homosexual, gay or lesbian.

“My Husband’s Not Gay” follows three (hetero) married couples and one single man. All the men featured admit to struggling with SSA. The couples and man reside in Salt Lake City, Utah, and cite their strong Mormon faiths as to why they have a traditional male-female marriage (or, in the case of the single man, why he wants one). Since conservative Christianity, and Mormonism in particular, has traditionally frowned upon homosexuality, these men have made a decision to honor their faith and not their attractions.

I wanted to find some stats on SSA, but couldn’t find any information that weren’t connected to any religious sites (of the “pray the gay away” stripe). Apparently, no university has done a study with people who experience SSA but who do not identify as gay, lesbian or bisexual. (Kinsey Institute, get on this.)

How Many People Fantasize About Having Sex With Identical Twins?

Twins Jordan and Zac Stenmark (Lyra Mag)

I read an NPR article on twins recently, calling millennials “Generation Twin.” This name applied due to the fact that one million more twins were born between 1980 and 2012. (This checks out with my personal anecdotal evidence: I graduated high school in 2004, and my class of 106 students boasted three sets of twins.)

“The Atlantic” goes a bit deeper into why this is: The rise in twins is due to the rise in fertility drugs, most notably IVF. Older women are the ones mostly using fertility drugs, and producing most of the babies. Also, older women are statistically more likely to have twins than younger women.

Here’s a handy table to visualize the rise in twins over the past decades:

Twins’ birth rate, 1980-2012 (The Atlantic)

That got me wondering if sexual fantasies about twins (both identical and fraternal) have also increased.

After doing some digging, I really couldn’t find anything. I didn’t find any studies about sexual fantasies, or fantasies coming true, involving twins.

The closest I got was the recent study on sexual fantasies by researchers at Canada’s University of Quebec at Trois-Rivieres, published in the “Journal of Sexual Medicine.” “Business Insider” helpfully took all the data for male fantasies and put it together. The closest question the researchers asked the 717 men used about twins was about having sex with two women. Over 84% of men reported this fantasy, but we cannot extrapolate that this necessarily means twins.

The identical-twin fantasy didn’t show up for the women either, but that’s perhaps more understandable: Women aren’t generally depicted as having that particular fantasy (though I’m sure there are some outliers).

I find it strange that a fantasy that looms so large in popular culture (for men, at least) has basically no data to back it up.

Women’s Opposite-Sex Friends Leads to More Sex in Relationships

Woman and Men At Work (via Black Enterprise)

Happy Friday! A recent study from the Journal of Comparative Psychology revealed something interesting: Attractive, heterosexual women who report more male friends also report more sex within their relationships.

The study surveyed 393 men in committed sexual relationships who described their partners as attractive. The more male friends their female partner had, the more sex they had in their own relationship. The men clearly were subconsciously reacting to competing with other (platonic) males.

As the abstract notes:

“This research is the first to empirically investigate the number of potential male rivals in the local environment as a cue to sperm competition risk in humans.”

Too bad the self-reporting didn’t extend to finding out who generally tended to initiate sex within the relationship.

Gallup’s 2013 Interracial Marriage Approval Rates

Gallup 2013 Interracial Marriage Results

Within the past few years, there’s been a lot of talk about the changing face of America (as “National Geographic” called it last year), in terms of racial demographics. It’ll change a lot more in the coming generations. In 2013, Gallup conducted a poll to find how Americans felt about interracial marriage.

The 2013 Minority Rights and Relations poll found that 87% of American adults approve of interracial marriage, with 84% of whites and 96% of non-Hispanic blacks approving. (This latter distinction is important because Hispanics were counted 1968-2003.) The survey comprised 4K+ Americans, with 1K+ identifying as non-Hispanic blacks. Interracial marriage was defined as one between “whites and non-whites.”

Since the 2011 poll taken two years prior, whites’ approval crept up one percentage point to 84%, while non-Hispanic blacks’ approval held steady at 96%.

The study also examined how the approval broke down by age and geographic location. Unsurprisingly, the Millennials and Generation Z (18-29 age range) lead the charge, approving by 96%. The 30-49-year-olds approval rate tracks closely behind at 93%. For the older groups, there’s less approval (which makes sense as they reflect the times in which they grew up): Ages 50-64 approve at 84%, and ages 65+ approve at 70%.

In terms of geographic region, the West wins out with approval ratings of 93%. Next up, the East and Midwest tie with 86%. With the South, old habits die hard, and it brings up the rear with approval ratings of 83%.

I’m now interested to see how approval of other interracial relationships shake out, such Caucasian/Hispanic, Asian/Black, etc. I think Gallup needs to examine these next.

But it’s very interesting to see how things have changed over almost 60 years: When the study was first produced in 1958, only 4% of Americans approved of interracial marriage. Now, the percentage is heading that way for those who disapprove. The trends are positive for Team Love!

How Female Orgasms Influence Mate Choice

Orgasm

Happy Friday! Here’s something to fun to keep mind as you head out for the weekend:

A new study claims that female orgasms influence beneficial mate choice: The more orgasms a woman has was directly correlated to her partner’s income, confidence and attractiveness. But it’s not all about quantity. Orgasm intensity was related to sexual satisfaction in terms of intercourse frequency and “how attracted they were to their partners.” Makes sense, right? (“Salon” breaks it down into less-scientific terms.)

The study analyzed “heterosexual female college students in committee relationships,” but doesn’t go into detail about these subjects. What was their average age? How long had the couples been together, on average? How times a week were the couples having sex on average?

Sounds like an excellent way to make a positive mate choice to me.

Sex & Stats: Where Numbers Come to Bang

Statistics. Economics. Sex.