Facebook on Thursday added custom gender options for users to identify themselves other than "male" and "female."

Users now can identify themselves as bigender, androgynous, cisgender, or in one of more than 50 ways. The move initially applies only to the company's 159 million monthly users in the U.S.

Facebook plans to provide the additional options to users outside the U.S. as well, but it did not reveal a time line.