Meaning of Milk from Impregnating Agent (the Father)

4. A number of our people have narrated from Sahl ibn Ziyad and Ali ibn Ibrahim has narrated from his father from Ahmad ibn Muhammad from ibn abu Nasr who has said the following: “I once asked abu al-Hassan عليه السلام, about the case of a woman who breastfeeds a girl and her husband has a son from another woman if it is lawful for this boy, the son of her husband to marry the girl she has breastfed. He (the Imam) said, ‘The milk is from ‘impregnating agent’ her husband.’”