Does Islamic law permit aborting a fetus if it is confirmed to be afflicted with or carrying a serious genetic disease, with a 50% probability of males being affected and females being carriers of the disease?

Abortion is Islamically forbidden and is not permissible unless the pregnancy poses a definite threat to the mother's life, as confirmed by a reliable medical report, or if the fetus has died inside its mother's womb. A fetal illness does not justify abortion. You must have a good opinion of Allah and be persistent in supplicating to Him so that He may heal your child, for the Prophet, peace and blessings be upon him, said: "Nothing averts destiny except supplication." You should also give charity frequently, for he, peace and blessings be upon him, said: "Cure your sick ones with charity."