Why do feel so attached to this baby?

The baby was conceived from a highly traumatic event, and it's not at all uncommon for women to find themselves unable to connect with a baby born in the midst of trauma. She's not a monster, she's someone who has been through something horrible and is having a fairly common psychological response.

Ultimately as the biological mother it's up to her to decide what happens to the child, and since you have no biological relation then legally you have no rights. If you want to be in the child's life and her adoptive parents are okay with you being involved, I think that's great. But you CANNOT hold the mother's situation against her. It's not right or fair. Since she has found herself unable to bond with the child, she has done the right thing by giving her to other adults who can properly care for her. She cared enough to realize that she can't be a good mother to this particular child, and that takes a lot of self-awareness. The only option you have is to accept the decision and hope for the best.

I hope you are a troll. It's better than being an insensitive so-and-so, who can't understand why a woman whose pregnancy was the result of rape can't bring herself to raise the child. You may wonder why she didn't 'just have an abortion'. Maybe she feels very strongly that it would have felt wrong for her, even if she'd understand someone in similar circumstances doing it. Maybe it was too late, by the time she knew she was pregnant.

I commend her for caring enough to let her family raise her daughter. The baby might have grown up in an institution. She might also have been adopted by a couple, that the mom knew nothing about.

You're annoyed she doesn't feel attached to a baby that was conceived when she was sexually assaulted? She gave the baby to her parents to raise. That was her choice. Butt out.

Perhaps this is because you truly care about the woman, and this child is part of her, and likely somehow reflects her in it's essence, as well.

If you were drawn enough to her when you dated, you may then have also wondered what it would be like to have a family with her . . .

I am guessing you actually may have relatively strong feelings toward the woman?

Of course, we are assuming this child could in no way be assumed to even possibly be yours, since you say she was "raped"?

Could the woman be depressed? There is what is called "post partum depression", and pretty likely in this situation. Perhaps she is suffering from this?

It sounds like you really need decide how you feel about this woman. If the child is safe with the grandparents, that's good.

Are there feelings yet to sort out between the two of you? That may be the point you need to concentrate on, and especially since she is "running to you". The baby will likely be fine where she is. You have to decide how you feel.

You feel attached because your brain released the bonding hormone oxytocin when you held the baby.

It means nothing. You wouldn't feel the same if you had to deal with the screaming, pooping, expense and sleep deprivation that is the reality of babies.