It can be something wonderful, but keep in mind it is a baby you are talking about, and that person should be treated no differently than your "own" baby, and raised with love.
I too find the idea quite hot, and I know if I get my wife into it, a real possibility. I got a taste of it when we had our baby. Many people thought I was not the *******, and several made it quite clear. Even my ******* at first was sure it was not my kid. For a while I was starting to think it was true, and was very turned on while at the same time loving my wife and our baby. It is clear now it is my baby, but I know I could handle it if my wife was to have a kid with another man, and it would be the ultimate if she was to do it with a Black Man.