If a gay illegal man come to the USA and marries a gay USA man; does that make the gay illegal legal?

Marriage in and of itself does not make someone legal, especially if the person has been in the country illegally previous to the marriage. Someone can be sponsored to come here on a fiancee visa, then receive a green card after marriage; but they would still have to go through the five-year process for citizenship.

Note that the laws have changed, and same-sex marriages are recognized for federal benefits, including immigration; so if the marriage was legal, and the partner entered legally, he could be sponsored.

Yes, it's a consequence of the DOMA decision from last year that spouses in a same sex marriage will be able to apply for legal status just like opposite sex spouses.

No. You don't become a citizen or 'legal' because you've married an American. Many Americans have married overseas and their spouse has been denied entry into the U.S. Marriage to a U.S. citizen isn't the shortcut that many still believe it to be.

Homosexuality is irrelevant.

It can, yes. There is more to it than that but yes it could give the undocumented person legal status.

No, you have to apply for a permit to be in the country first

No, just makes him gay

No. He is married to an American.

yes it can

No.