May one marry a woman which cannot have children?
One who has not fulfilled the Mitzvah of Peru Urevu may not to marry a woman who cannot have children, such as an old woman, child or a woman who is baron. From the letter of the law, one who marries such a woman is to be protested. However for many generations the custom is to not be particular about matches and hence no issue is made regarding ones choice of marriage.
 Rama 1/3