According to the World organisation of public health services, 10-15 % of all married couples have no children. These are so-called fruitless marriages.
And it is far not always in a role 'guilty' the woman acts.
On a share of men it is necessary not less than 35 % of all cases of sterility, and only in 20 % of cases 'fault' for absence of pregnancy both spouses carry.
In cities of fruitless marriages it is even more - to 30 %, and at least in half from them the man is not capable to have children.
Here such depressing digits confirming that a fecundity (ability to posterity reproduction) a strong half of mankind falls. Because of a bad bionomics, a wrong food. Not last role is played also by the deficiency of physical activity reducing potential of a fecundity of the man on 1-2 % a decade.
However, all these factors are shown not so much at healthy, how many at those who included into risk group. First of all it is men who for 10 and more years are more senior the spouse.