Healthy Seventh-day Adventists vegetarians, maybe longest living, but might that come at a cost.

A semen analysis at a fertility clinic in Loma Linda, California, home to a large population

of Adventists, raised questions

about their sperm quality.

Though still within the normal range, vegetarians had about a 25% lower sperm count.

The few vegans tested also had a lower sperm concentration, but they made up for that,

with their 30% greater ejaculate volume.

The vegans did have significantly fewer activated sperm, though, which is a sign of decreased

fertility.

The researchers suggested soy consumption as a possible mechanism, as Adventist vegetarians

in California average about a half-serving a day of plant-based meats, many of

which contain soy.

Soy phytoestrogens have been put to the test, though, and months of consuming up to the

equivalent of nearly 20 servings of soy a day did not result in any adverse effects on sperm

parameters.

There were only five vegans in the study, so the sperm quality findings could just

be a fluke, but if verified, this could reflect an evolutionary trade-off between fertility

and lifespan first proposed nearly a century ago.

Using a finely tuned laser, it's possible to selectively destroy individual cells as the tiny

roundworm sea elegance develops, and terminating the cells that give rise to sperm

and eggs significantly extends lifespan.

The same phenomena can be demonstrated in fruit flies, potentially shifting the

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