Jay-Z is a big fan of president Obama and he supports the presidents' decision to back gay marriage whole heartedly.
Jay-Z's support for gay rights must be a fairly recent development, since some of his past lyrics have demonstrated views that could be viewed as being, shall we say, gay unfriendly.
For example, here are some lyrics from his hit "Lucky Me":
"Niggas wanna strip to the bone for shit you own
Hate a nigga like that faggot, get your own."
Or this gem from the song "Heart of the City:
"More money, more problems" - gotta move carefully
'cause faggots hate when you getting money like athletes."
They sure do Jay. They sure do.