http://www.slate.com/id/2140494/Predators and PreemiesWhy old men shouldn't impregnate young women

Older men are more likely to produce premature babies. For a mother 20 to 24 years old, the risk of bearing a child before 32 weeks' gestation almost doubles if the father is 45 to 49 years old rather than 25 to 29. The younger the mother, the stronger the effect. Previous studies have linked older fathers to some pregnancy complications, birth defects, and diseases in offspring. Interpretations: 1) Men may accumulate bad mutations as they age or are exposed to toxins. 2) Nature may discourage big age differences between parents because they're disadvantageous to the child. 3) For God's sake, she's young enough to be your daughter. (For Human Nature's take on polygamy, click here. For incest