Jami At Tirmidhi
1149
Sahih Isnaad+2

Amr bin Ash-Shariq narrated that Ibn Abbas was asked about the case in which a man had two slave girls, one of them suckled a girl and the other suckled a boy, is it lawful for the boy to marry the girl? She said:“No, the semen is the same.”

Sahih IsnaadAhmad Muhammad Shakir
Sahih IsnaadAl-Albani