I am a Canadian married to US citizen.
The question is where will you stay in US? or Canada?
There's no restrictions when you want to marry to anyone whatever his nationality.
I think you concern about immigration.
I have a problems before the gay marriage overturn in US, because the federal government in US doesn't recognize gay marriage until 2013 June. Now the trouble is gone.
For immigration issue, yes it has to have health screening/ checking. It seems not too hard unless you have a serious medical issue.