Can you tell a baby boy from a baby girl?

I had just rolled up to a checkout line at the grocery store when the cashier began to coo over my baby.  We get that a lot.  She's awfully cute.  That day, she was sporting an especially adorable blue sweatshirt with a small ruffle around the neck, and the corduroy pull-ups from Baby Gap mentioned in a previous post.

The cashier was a big guy, I'm guessing upwards of 300 pounds, which made his effusiveness all the more fun.  "Who's mama's big boy?" he gushed.  "You certainly are a big strong baby boy, aren't you?"

"Oh...," I said, "um, thank you!"

Sometimes it just isn't worth it to me to correct people when they think my baby is a boy, not a girl.  I don't really care at all if they get it wrong, but when I do correct people, it seems to somehow upset them; they often wind up apologizing over and over, becoming especially vehement in their declarations of how pretty my baby is, etc. etc.  So this time, I didn't say anything.

But he went on and on.  And then 2 more people peered into the stroller and began making similar exclamations about what a big, healthy baby boy I had... .  At this point, I sort of wanted to correct them, but it had gone on so long that it was just not possible.  So I meekly paid and we made our exit.

And it got me thinking.  Is it even possible to tell a baby boy from a baby girl?  I mean, from the neck up, if they're not wearing any bows or baseball caps?



So, in true medical student style, I did a literature search!  And found...not much.  There's been only one study of sexual differences in children's faces.*

Heather Wild and colleagues at UT-Dallas performed an experiment** with both children and adults who were asked to categorize pictures of 7 to 10 year-old and 20 to 29 year-old faces as male or female.  Here's an example of what the pictures of adult faces looked like; the children's faces were presented in the same way, but no examples were published because of privacy concerns:

As you might expect, both children and adults were able to tell which adult faces were male and which were female (although adults were better at this than the kids were).  But what do you think?  Were children or adults able to tell which children's faces were male versus female?

The answer is yes, but much less accurately than for adult faces.  The A' value for adults judging the children's faces was around 0.75 (non-statisticians:  you can read A' as being roughly the same thing as 'percent correct', but the number's been adjusted a bit to account for the fact that participants tended to guess male more often than female), so adults got the gender right about 75% of the time for kids' faces, compared to about 100% of the time for adult faces.

I wish I could tell you about a similar experiment that was done with babies, rather than children.  But I can't, because no one's ever done it.  I'd be willing to bet that adults guessing babies' gender in a similar study would be right about, oh, 55% of the time.  But "it's an empirical question!," as my undergraduate research advisor used to love to say.  Someone should do the study.

Meantime, I can say that I think the super-gendered baby clothes that dominate stores are just silly.  It can be so difficult to find clothes that aren't blue or pink, especially for very young babies.  I've made an effort to get a variety of baby clothes; my daughter has some pink in her wardrobe, but I try to make sure that there's a sporty orange polo shirt for every polka-dotted sweater.

I think this is important because biased expectations of children start very, very early.  In the same issue of the same journal as the study described above, I stumbled across another experiment*** which asked mothers to estimate their 11-month-old son's or daughter's crawling skills and predict how their child would perform in a new crawling task up and down some sloped surfaces.

Interestingly, the mothers of baby girls significantly under-estimated their daughter's skills and future performance, while the mothers of baby boys significantly over-estimated their son's skills and future performance on the crawling task.  When the researchers actually measured the baby's skills and performance on a crawling task, there was absolutely no difference between the boys and girls.  The mothers were wrong; and not just wrong, but systematically wrong on the basis of their baby's gender.

So, if someone mistakes your baby for a boy rather than a girl, or vice versa?  Just shrug it off!  And keep those expectations high, regardless.

The offending gender-neutral sweatshirt that inspired this post!

*  That I could find.  Others with PubMed/Web of Science/Google Scholar savviness should see if they can dig anything else up.

**  Wild, H.A., Barrett, S.E., Spence, M.J., O'Toole, A.J., Cheng, Y.D., and Brooke,  J.  (2000).   Recognition and sex categorization of adults' and children's faces:  Examining performance in the absence of sex-stereotyped cues.  Journal of Experimental Child Psychology, 77, 269 - 291.

***  Mondschein, E.R., Adolph, K.E., and Tamis-LeMonda, C.S.  (2002).  Gender bias in mothers' expectations about infant crawling.   Journal of Experimental Child Psychology, 77, 304 - 316.