Introduction: You're about to have sex with your best friend's wife. You are Michael Foxwell, and the lady in question is Emily, who married your best friend Katie three years ago. The couple want to have children, and Emily wants to be the natural mother, to experience pregnancy, and childbirth, and the natural bond between mother and baby. Katie wants to feel that personal bond, too, and since she can't father a child herself she wants you to, because you have been her best friend since junior school, and she knows you'll be the perfect biological father. She's thrilled at the prospect, and you're happy to help. You assumed this would mean a visit to a sperm bank, but Katie is a naturalist, and insists on a natural conception.