Girls Only

Desperate to have a baby girl? Well you might think about relocating. Or eating more marine animals. 

Researchers have discovered several towns where women are only giving birth to
girls. The gender balance is totally out of whack and something like a
2 to 1 ratio of boys to girls.

Where are these towns of rainbows and ponies and sparkles and all Hannah Montana all the time?

They are Arctic communities up in northern Greenland. What’s causing this. Most likely, PCBs.

Here’s an excerpt of an interview with concerned researchers on NPR’s Living on Earth about the PCB-girl baby connection:

Now, looking at your report here I’m just struck by the apparent
effects that PCBs have on the sex ratio of children and the way it
changes … The chart
that you have there shows that as you increase exposure to PCBs, at
first you get way more boy babies than girl babies. But then as you go
higher and you get above four micrograms per liter of blood you get way
more girl babies.

How could this happen? Here’s what Lars Otto Reiersen, executive secretary for the Arctic Monitoring and Assessment Program, says: 

Well, it could be what we call the mimic of the hormones. That early in
the pregnancy that some of these pesticides may mimic testosterone or
estrogen. That’s documented from science. So, that might be what’s
occurring but that’s too early to say for sure what’s the mechanism.

Well that’s just kind of yuck. Plus, the girl babies with moms who have a higher concentration of PCBs in their blood have a lower birth weight and much earlier births. So it’s not all tea parties and frilly socks and two girls for every boy; there are serious health consequences.

Still, here’s what I don’t get. I thought gender had more to do with Dad’s sperm than mom. He’s the one shooting Y chromosomes for boys and X chromosomes for girls. Are they studying sperm in all this? Or are these children actually hermaphrodites — in this case technically boys with female characteristics? Or do I need to go back to sophomore biology?

Think it’s no big deal for those of us who are not dining on PCB-rich walrus fat? Actually, everybody around the world has some level of PCB exposure, just different concentrations of it depending on where they live and at what level of the food chain they typically eat. The next question is, what has the impact of low exposure been? 

Photo: bodis-wallner.com