From: Rabbi Moshe Sofer
To: Unknown recipient
A wife's father sought to compel divorce claiming the husband suffered from kidney stones making marital relations life-threatening, analogous to mukeh shechin, and that his physical weakness caused the wife's post-partum illness. The Chasam Sofer ruled firmly against compelled divorce, finding the medical evidence contradictory, the husband's presumed healthy status (chazakah) controlling, and that kidney stones do not in fact endanger marital relations. He warned that coercing a get on such grounds would risk producing mamzerim.
Source: Shu"t Chasam Sofer EH II §61