In Tunisia these animals are often caught and exploited because of the tribal belief that they may increase male fertility.

In agriculture, it is used to increase fertility in livestock.

There was a good supply of green food in winter which increased the longevity and fertility of the females.

After mating, the female may attempt to eat the male to increase fertility, which will entail a struggle.

The Ring is also rumoured to increase fertility in women who sleep underneath the trees for one night.

Gathering disasters usually increase fertility, as did the pollution disaster at first.

Israel is not to resort to the Canaanite practice of boiling a kid in its mother's milk to increase fertility.

In the current century, the past decade as of 2012, most advanced countries have increased fertility.

Or maybe there's something in Erehwon's soil that is increasing human fertility.