Normally in the development cities, almost people cant have babies when they are young, because the price in this countries are very high. This causes that men have child, when he has 30 or 35 years old. For example in United Kingdom the average is 40 years old.
But in this ages, is so difficult to have a babies, because the men started to cessation the production of sperm, and the fecundation are complicate. Other problem that in this cases we can find is that, if the egg is fertilized the woman can have problems in the pregnancy and the baby can born with a genetic defects.
Since of 35 years, men can have the Andropause, equivalent to menopause in women, that causes that they lose male hormones gradually, for this reason the men decrease in production of testosterone around of one or two per cent. For this problem we can find some solutions, but normally this are expensive, for this people prefer to do in-vitro fertilization procedure, this do women.
For the problems of infertility, the men can have, may be, reduction of ego, because they could feel that lose the masculinity.