It is narrated from Hazrat Anas (may Allah be pleased with him) that a man came to the Prophet (peace and blessings be upon him) and began to ask about coitus interruptus. The Prophet (peace and blessings be upon him) said, "That drop of water from which a child is created, even if it is poured upon a rock, Allah can create a child from it, and Allah will surely create the person whom He wants to create."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 12420
Hadith Gradingحکم دارالسلام:إسناده ضعيف، أبو عمرو مبارك الخياط فى عداد المجهولين