《史记·三十世家·外戚世家》
夫妇欢合之后，有的不能繁育子孙；能繁育子孙了，有的又不能得到好的归宿。
既欢合矣，或不能成子姓；能成子姓矣，或不能要其终。
After the husband and wife have intercourse, some cannot reproduce; if they can reproduce, some cannot find a good destination.