All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
A wife is prohibited from asking for divorce without a sound reason; the Prophet, sallallaahu ‘alayhi wa sallam, said: “Any woman who asks her husband to divorce her without harm, the smell of Paradise is forbidden for her.” [Ahmad]
As regards when a wife asks for divorce for a sound reason, this is permissible for her. Ibn Hajar said: “The reports that were reported about the warnings against a woman asking her husband for divorce are interpreted as meaning when there is no reason that requires that.” [Fath Al-Baari by Ibn Hajar (9/402)]
Thus, if it is scientifically confirmed that children born of parents such as in your case will carry this disease, then in our view – and Allaah knows best – it is permissible for you to ask for divorce for this reason.
Allaah Knows best.