Does BPA Make Men More Like Women?

Bisphenol A (BPA), the chemical found in plastic food containers and liners, is the focus of intense debate over its health effects.

Sure to add to the discussion is a new study from the Proceedings of the National Academy of Sciences that suggests exposure to BPA makes male mice a bit less manly.

The experiment exposed a group of male deer mice to BPA from the time they were born. The researchers say that once fully grown, the mice appeared perfectly healthy, but that female mice had no interest in mating with them.

In addition, the BPA-exposed mice didn't do as well on spatial navigation tasks that measure ability to find female partners in the wild.

To expose the male mice to BPA, the researchers fed their mothers a diet with levels of BPA that reflected the amount of the chemical the government says is safe for humans. Once the baby mice were weened, their exposure to BPA was removed.

The researchers said they were trying to determine whether exposure to BPA in the womb and as infants creates lasting effects.

Of mice and men

In the mouse world, males have a unique ability to navigate their way through a maze. It is less-developed in females, since females do not seek out mates in the wild. Rather, it is the males who seek the females. 

When placed in a maze, the BPA-exposed mice reportedly were not up to the task. When the BPA-exposed mice were placed in the company of females, along with males who had not been exposed to BPA, the scientists said the female mice preferred the unexposed rodents by a factor of two to one.

Subject of wide study

BPA has been widely used for more than four decades, though the Food and Drug Administration is only now taking another look at its safety. Several studies have raised questions about BPA's impact on reproductive health, through the food industry insists the chemical is safe.

Among the more widespread uses of the chemical are as a hardener in plastic beverage bottles and in the plastic liners on the inside of metal food cans. The FDA announced in January 2010 that it would again study the chemical's safety.