Size does matter!

PHILADELPHIA Oct 21, 2004 � Beer bellies may take a toll on men below the belt, not just around it. Men who weigh too much are more likely to have poor sperm quality, research on nearly 1,600 young Danish men has found. Being too thin is a problem, too.

Women don't get off the hook. Though it's long been known that very overweight women have trouble conceiving naturally, a large new study confirms they also are less likely to become pregnant even when embryos are fertilized in lab dishes and placed in their wombs.


abcnews.go.com...

Sperm counts and sperm concentration were 28.1 percent and 36.4 percent lower respectively in underweight men. The same measures were 21.6 percent and 23.9 percent lower respectively in overweight men.

Yet another reason to stay in shape and try to maintain a normal weight. This may be natures way of trying to keep a balance, by making it harder for less healthy people who may pass on this trait to their offspring. Survival of the fittest so to speak!

I wonder, though, how much is related to weight, and how much is related to good nutrition. It could be a nutrient that is missing that prevents pregnancies in women, and reduces sperm production in men. This might explain why the superthin also have similar issues - they don't eat enough! Perhaps the fat increases blood pressure enough that the delecate mechanisms that nurture babies and produce sperm can't operate. Could be that the fat causes changes in hormones and body chemistry enough to prevent normal reproductive function.

Somewhere I've read that many pregnancies end before women even know they are pregnant as bodies know when something is wrong with the fetus and expell it. Could it be something like overweight women are less likely to get something like folic acid in their diet, so they have a higher number of defects, and a higher number of spontaneous abortions in the first few weeks before they even know they are pregnant?

It's a good example of "survival of the fittest" as you pointed out above. If bodies aren't in good shape health wise, their genes are least likely to be passed on. Doesn't explain why America gets fatter and fatter - you'd think there would be some self-selection when so many people find overweight people to be somewhat unattractive. Hmm...