Washington, D.C. — The annual number of gay dads and lesbian moms adopting children has tripled in the past decade, new census numbers show.

In 2000, 6,477 same-sex couples reported that they had adopted a child. In 2009, the number jumped to 21,740.

The total number of adopted children living with gay and lesbian parents was approximately 32,500 in 2009. 

The spike is partially due to the fact that many states have eliminated rules barring gay and lesbian parents from adopting children from foster care. In the past, gay and lesbian parents who wanted kids often paid for a surrogate or adopted a child from a foreign country -- both of which can be expensive.

The Adoption Institute told the Associated Press that 60 percent of American adoption agencies accept lesbian and gay parents.

But a demographer with UCLA's Williams Institute told the AP that the total number of gay and lesbian parents is declining as homophobia wanes. That's because most gays and lesbians come out of the closet early in life -- and don't go through a straight marriage first. So fewer lesbian and gay couples are raising children from prior, heterosexual marriages.