Baby, You Gotta Have Balls

Let’s talk about boys and their balls. The kind that dangle between legs and not, ideally, the kind you hit with a baseball bat.

I found myself thinking about the cultural and biological importance of baby balls -- and masculinity, really -- one morning not long ago as I lay in bed, scrolling through my e-mail on my smartphone. I’m about seven months pregnant, and like most moms-to-be that I know, I signed up to receive weekly e-mail updates about fetal growth and development.

On this particular day, I skimmed along until I read a passage that went something like this: "Congratulations! If you are having a boy, his testicles are beginning to descend." A baby’s testicles, the e-mail told me, develop inside his abdomen until the last trimester of pregnancy, at which point they begin to move to their rightful place, hanging between his little legs.

Or maybe not, I thought.

Cryptorchidism, the medical term for undescended testicles, is among the most common birth defects in the United States. It affects about 1 in 30 boys, and although it can be corrected surgically, the condition has been linked with fertility troubles later in life. The problems that lead to undescended testicles begin very early on, scientists believe -- possibly during mom’s first trimester, or maybe even earlier, before dad’s little swimmers have even met up with mom’s egg.

Over the past decade, scientists have built an increasingly strong case indicating that some chemicals interfere with male sex hormones in the womb. Cryptorchidism is just one facet of what has become known as "phthalate syndrome," named for a class of industrial chemicals called phthalates, which are used to make such things as the plastic PVC (polyvinyl chloride), as well as many personal care products. Phthalate syndrome has been well documented in rodents, and there is a growing body of evidence suggesting that humans are suffering, too.

If there is a doyenne in the field of phthalates and their effect on little boys, it is Shanna Swan, a reproductive epidemiologist who is now at Mount Sinai Medical Center in New York City. She spent much of the past decade at the University of Rochester, studying fertility.

One of the things scientists measure when they study the effects of various chemicals on the reproductive systems of animals is referred to as the AGD, which stands for anogenital distance -- or, as you may have deduced, the distance from the anus to the genitals. On average, males have an AGD that measures about twice that of females, making it something of a yardstick for gauging relative maleness or femaleness. If a male rodent has a very short AGD compared to other rodents of the same species, the conclusion is that whatever the chemical under investigation was threw his male sex hormones out of whack when he was still in the womb.

Tipped off by animal studies, Swan started looking for signs of phthalate syndrome in humans. Through a larger fertility study she was conducting at Rochester, she began measuring traces of phthalates in pregnant women’s urine and later found that those with the highest levels gave birth to boys with abnormally short AGDs.

She then recruited a group of college-age men on the University of Rochester campus to look for relationships between AGD and sperm quality. A fraternity pledge class and an entire sports team signed up and each left behind a questionnaire, a sperm sample, and an AGD measurement.

Ultimately, she discovered, size (or in this case, distance) does matter. Those with AGDs below the median were 7.3 times more likely to have sperm counts below the level at which a man is considered to be fertile than those with AGDs above the median. (For the curious out there, the median was 2 inches, adjusted for overall body build. And note to those looking to pull out the tape measure during their son’s next diaper change: This measurement applies to grown men, so don’t get worried.)

All told, Swan’s results, as well as national surveys conducted by the federal Centers for Disease Control and Prevention, suggest that about 25 percent of pregnant American women may have enough phthalates in their bodies to interfere with the reproductive systems of their male children.

Alas, a pregnant woman cannot turn to her doctor for a phthalate test in the same way that she can get a blood-lead test. But if she could, as with lead exposure, a high test result could indicate increased likelihood of harm, prompting a direction or two on limiting phthalate exposure.

But how do you avoid phthalates?Some of the nastiest types of phthalates are those used in the production of vinyl products, many of which are involved in processing foods -- think of tubing that moves milk from a cow’s udders to a vat for pasteurizing, or the vinyl gloves that food workers wear as they’re sorting and packing lunchtime edibles.But are you going to skip milk altogether? Probably not. So what else can be done? Cutting out processed foods helps. And given that phthalates are often used to make pesticides, eating organic helps, too. At home, try to avoid installing flooring, mini-blinds, shower curtains, and other products made of PVC (there are plenty of non-vinyl alternatives).

And then there’s the worst offender among personal care products: perfume. Phthalates are used to help make fragrances stick to the skin and last longer, but you often won’t see the chemical listed as an ingredient on the label.

My husband, Peter, is used to my fanaticism about eliminating unwanted industrial chemicals from our lives. He knows to look for organic produce in the store and, for the most part, leaves the purchasing of cleaning products and other home items up to me. But when we were riding in the car a few days ago and I explained the phthalate-fertility link, he gave me a stone-faced look. Do whatever it takes, he said, to avoid emasculating our future sons.

In the interest of full disclosure, we know we’re having a girl, which don’t seem to be affected by phthalates in the womb. But next time around, I have no doubt that Peter will be a little more interested in making sure I’m eating organic foods and avoiding exposure to chemicals during those first crucial months of pregnancy. He’s already stopped me mid-bite to say that next time, I’ll need to avoid eating the highly processed Peppermint Patties that I’ve become so fond of lately… just in case.

Of course, there are other factors involved in all of this -- genetics, to say the least -- but if there’s one way to guarantee that fathers everywhere will pay more attention to the chemicals that enter their wives’ and kids’ bodies, it’s to tell them their son’s chance of being born with a big ol’ pair of brass ones depends on it.