From Abu Dawud, Book 11, Number 2045:
Narrated Ma'qil ibn Yasar: A man came to the Prophet (peace be upon him) and said: I have found a woman of rank and beauty, but she does not give birth to children. Should I marry her? He said: No. He came again to him, but he prohibited him. He came to him third time, and he (the Prophet) said: Marry women who are loving and very prolific, for I shall outnumber the peoples by you.