Reference: Fataawa wa Rasaa.il Mukhtaarah – Page 577-578
Question: I testify to Allaah (Ta’aala) that I love you for the Sake of Allaah! I [would like to] ask [you] about the ruling regarding artificial insemination, where a man does not have children, and the doctor has informed him his sperm count is low, and this will necessitate medically impregnating the womb of his wife with his sperm. So I ask you to pray to Allaah that he blesses me with noble offspring, and may Allaah protect and preserve you?
Response: If the situation is as the questioner mentions, then it is permissible to draw sperm from him using medical equipment, and then insert it into the womb of his wife – with the [strict] condition that [all] the medical equipment is [functionally] sound, and the doctor is honest and trustworthy in assuring the sperm which will be inserted into the womb of this man’s wife is his sperm and not that of another man.
And we ask Allaah to bless him with noble offspring, for indeed He is the One Who Hears the supplication.