What is the ruling on marrying a woman who, after marriage, is discovered to be infertile due to a birth defect that she and her family were aware of, and what should the husband do when his first wife gives him the choice between divorcing her or divorcing the second wife?

If the marriage fulfills the conditions of validity, it is valid, and the wife's defect does not affect its validity. The wife does not have the right to demand a divorce merely because the husband has married a second wife. The husband has the choice between divorcing his wife or keeping her. It is more preferable to divorce if the purpose of the marriage is not achieved, because the continuation of the marriage might be pure corruption and pure harm. It is recommended for someone who is infertile to disclose that before marriage, because procreation is one of its most important purposes.