As we have learned, a saris rendered sterile by human intervention may not marry a Jewish-born woman, but may marry a convert or a freed slave (m. Yevamot 76a).[2]
We have also seen that the prohibition does not apply to someone born sterile. If someone was rendered sterile as the result of illness, poskim disagree as to his status. According to Rosh, such a person may not marry a Jewish-born woman. Since humans play a role in the contraction of diseases, for example by eating unhealthy foods or by polluting the environment, such sterility is seen as being man-made. In contrast, according to Rambam and most Rishonim, a person who became sterile due to illness is considered to have been made sterile by God, and may thus marry into the community. The halakha follows this position (Yam Shel Shlomo; Mishkenot Yaakov; Birkei Yosef; Pitḥei Teshuva 5:7; Maharsham; AHS 5:18).
We learn an important principle from the law that a born saris may marry: Normally, the mitzva of ona is considered the foundation of marriage. Accordingly, if someone wishes to marry on condition that he is not obligated to fulfill the mitzva of ona, the marriage does not take effect (SA EH 38:5; above ch. 1, n. 2). Nevertheless, if due to circumstances beyond his control – for instance, he is a born saris – a man cannot have sexual relations with his wife, the marriage does take effect. We therefore see that it is possible for a couple to base a marriage on their emotional connection and their commitment to be good to one another.[3]
The prohibition is for a man who became a saris to marry a Jewish-born woman. However, a woman who underwent a procedure of sterilization (for example, a hysterectomy) is permitted to marry a Jewish-born man (Sefer Ha-ḥinukh §559; Otzar Ha-poskim 5:1:1). Nevertheless, a man who has not yet fulfilled the mitzva of procreation may not marry her, as doing so makes it impossible for him to fulfill his obligation to procreate (above 5:8).
[3]. The mitzva of ona includes caressing, as well as anything which brings joy to one’s spouse, as we have seen above in 2:3. Thus, it is a mitzva for a saris to do whatever he can to bring his wife pleasure, including physically pleasuring her to the best of his ability. Even if we were to argue that without the possibility of sexual relations, foreplay and other affectionate behavior do not fulfill the Torah requirement of ona, they are still part of the obligation of “love your fellow as yourself.”