Alright it seems you or the hypothetical person/friend whatever isn't comforatable with the situation and is looking for someone else to afirm that discomfort. I think that helping your sister out would be a beautiful wonderful gift. At the same time, if your not comfortable with the conditions, than don't feel like your a bad person. I can understand reservations about the husband, hes seems like scum. Also you mentioned possibly wanting kids down the road, and potential complications with the procedure. If your uncomfortable with all this, then don't be afraid to say no to your sister. I think the weirdness issues are not as big as you make them out to be ie. looks like you, child won't know etc etc. I think the father and your future children are the biggies here. If your sister is that intent on having a kid... then she can go outide her gene pool, or even adopt. Just some thoughts... I'm no expert, but I kind of live by the if it feels right life motto, and it seems to me like things aren't feeling right!