Members of the LGBT community can no longer be discriminated against when it comes to marriage based immigration benefits thanks to the landmark decision of the U.S. Supreme Court in United States v. Windsor, which invalidated DOMA (Defense of Marriage Act).

A U.S. citizen or legal permanent resident who is validly married to a foreign national may sponsor his or her spouse for a family-based visa, regardless of the gender of each partner.  This will allow the alien to seek lawful permanant residence in the U.S. 

If a couple is not yet married and the alien is residing outside of the United States, the alien may be eligible to apply for and receive a K-1 fiance visa that will allow him or her to come to the U.S. and get married.  After the wedding takes place, the alien will then be eligible to apply for a green card.

Consultation with an attorney expeienced in immigration is advisable to navigate the complexities of immigration law  and avoid pitfalls.