Sterility neither prohibits nor nullifies marriage when there is no deception about it because it “by its very nature can gravely disturb the partnership of conjugal life”.
CIC Canon LawCHAPTER III.
SPECIFIC DIRIMENT IMPEDIMENTS
Can. 1083 §1. A man before he has completed his sixteenth year of age and a woman before she has completed her fourteenth year of age cannot enter into a valid marriage.
§2. The conference of bishops is free to establish a higher age for the licit celebration of marriage.
Can. 1084 §1. Antecedent and perpetual impotence to have intercourse, whether on the part of the man or the woman, whether absolute or relative, nullifies marriage by its very nature.
§2. If the impediment of impotence is doubtful, whether by a doubt about the law or a doubt about a fact, a marriage must not be impeded nor, while the doubt remains, declared null.
§3. Sterility neither prohibits nor nullifies marriage, without prejudice to the prescript of
⇒ can. 1098.
Can. 1098 A person contracts invalidly who enters into a marriage deceived by malice, perpetrated to obtain consent, concerning some quality of the other partner which by its very nature can gravely disturb the partnership of conjugal life.
Gaudium et Spes 48 (Vatican II)
For, God Himself is the author of matrimony, endowed as it is with various benefits and purposes.(1) All of these have a very decisive bearing on the continuation of the human race, on the personal development and eternal destiny of the individual members of a family, and on the dignity, stability, peace and prosperity of the family itself and of human society as a whole. By their very nature, the institution of matrimony itself and conjugal love are ordained for the procreation and education of children, and find in them their ultimate crown. Thus a man and a woman, who by their compact of conjugal love “are no longer two, but one flesh” (Matt. 19:ff), render mutual help and service to each other through an intimate union of their persons and of their actions. Through this union they experience the meaning of their oneness and attain to it with growing perfection day by day. As a mutual gift of two persons, this intimate union and the good of the children impose total fidelity on the spouses and argue for an unbreakable oneness between them.(2)