Of course God is sovereign over conception. But that does not mean that man has nothing to do with it. There are all kinds of things we do that may decrease fertility, and also all kinds of things we can do to increase fertility. Some women wean their babies early in an attempt to regain their fertility. Some couples make a special effort to have intercourse when the woman is aware that she is at a fertile time of the month. Other couples, having discovered that the husband has low sperm count, may at fertile times ensure they only have sex every other day not every day so as to increase the chance of conception.