Meaning of Milk from Impregnating Agent (the Father)

8. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from Ali ibn Mahziyar from who has said that ‘Isa ibn Ja’far ibn ‘Isa who has said the following: “This is concerning my question before abu Ja‘far, al-Thaniy عليه السلام, about a woman who breastfeeds a child for me: if it is lawful for me to marry a daughter of her husband. He (the Imam) said, ‘It is a very good question. It is because of this that people say, ‘His wife has become unlawful because of the milk of ‘impregnating agent’ (husband).’ This is the milk of ‘impregnating agent’ and nothing else. I then asked, ‘The girl is not a daughter of the woman who breastfed her. She is a daughter of another woman.’ He (the Imam) said, ‘Even if they were ten different women, no one of them would have been lawful for you because of being as like your daughters.’”