I was thinking about the hormone levels when I was wondering about the age issue, and I also wondered about how it would affect the relationship - how would her mother feel after giving birth, would she feel it was her baby or her grandbaby? A friend of mine gave up her baby for adoption by her SIL, and then she came here and stayed with her SIL and BIL for six months till she and her husband got good employment and were able to stay on their own. I used to wonder how it would feel for her to live in the same house with her son being officially not her son, and would she feel uncomfortable if her son was being disciplined by her SIL and BIL, or if her son went and hugged his adoptive parents, calling them Mom and Dad (her other children didn't know about this adoption, nor did her SIL's daughter). I think it makes for difficult relationships and it would take a very mature attitude all around for this to work.