^ You need to look up adoption in Islam. You must make it clear from day one that you (and your wife) are not the chlid's real father. However, looking after orphans or needy children are strongly encouraged.
Also, we must keep in mind that polygyny is permissible in Islam; but that does not mean you must practice it or it's even recommended (you'll have an entire new category of questioning if you have more than one wife). But yeah, you only said you disagree with it for yourself; I hope nobody starts to assume things and we have a copy-paste of articles rush.
lol I appreciate the look out. I know polygamy is permissable, but personally, I don't agree with it.
As far as adoption goes, I have no intention to claim to be the child's original father anyways, If I ever have to resort to adoption. Its a bridge I'll cross if I ever get there, because as of right now I'm not yet married.