The British comedy Monty Ponthy sings 'Every sperm is sacred.' The OP in this story believes this whole heartedly and doesn't want her fiancé to donate his sperm to his infertile brother. She doesn't want her fiancé to donate because she is worried about the implications and possible negative impact to her future family. The older brother cannot have a child and asks his younger brother for help. Some think it's incredibly manipulative of the BIL to say that this the 'only chance' he can have a child, even though he didn't consider an anonymous donor or adoption. Others think that the little brother and fiancé are making a fuss out of nothing. Sperm is sperm. It won't be their child to care for, they would just be doing a kind gesture to help the BIL start a family. The moral Judges of Reddit are having a field day with this one.
https://cheezburger.com/15386373