Facebook users who do not want to identify their gender as male or female now can select from around 50 other terms.
Among the new ones added by the social network site are androgynous, bi-gender, cisgender, intersex, gender fluid and transsexual.
There are also three preferred pronoun options: him, her or them.
The company said the changes were aimed at giving people more choice in how they describe themselves.
The move came after years of lobbying from users, some who started Facebook pages to petition for the change.
Facebook worked closely with lesbian, gay, bisexual and transgender (LGBT) activist groups to compile the new list of gender identity options.
Company spokesman Will Hodges told Techcrunch.com: “While to many this change may not mean much, for those it affects it means a great deal.
“We see this as one more way we can make Facebook a place where people can express their authentic identity.”
Facebook software engineer Brielle Harrison worked on the project and is herself undergoing gender transformation, from male to female.
She said: “There’s going to be a lot of people for whom this is going to mean nothing, but for the few it does impact, it means the world.
“All too often transgender people like myself and other gender nonconforming people are given this binary option, do you want to be male or female? What is your gender?
“And it’s kind of disheartening because none of those let us tell others who we really are.
“This really changes that, and for the first time I get to go to the site and specify to all the people I know what my gender is.”
But the latest development seemed senseless to those who believe in two genders.
Jeff Johnston from national religious organisation Focus on the Family said: “Of course Facebook is entitled to manage its wildly popular site as it sees fit.
“But here is the bottom line: It’s impossible to deny the biological reality that humanity is divided into two halves – male and female.
“Those petitioning for the change insist that there are an infinite number of genders, but just saying it doesn’t make it so. That said, we have a great deal of compassion for those who reject their biological sex and believe they are the opposite sex.”