My sister-in-law imparted to me the sexual

After I got into college, I lived in the house my brother bought in the city. My sister-in-law is very voluptuous and beautiful, but despite being married for many years, they haven't had any children. One night, when I got up, I accidentally overheard a private conversation between my sister-in-law and my brother: "You can't have children, but I want a baby. Why don't you let your brother help me get pregnant..."