Houston Mayor Annise Parker on Friday provided powerful testimony on what marriage means to gay and lesbian couples.

The openly lesbian Parker is one of the more than 75 mayors joining the nascent group Mayors for the Freedom to Marry.

Mayors involved will lobby state lawmakers to approve marriage equality legislation and call on Congressional representatives to repeal the Defense of Marriage Act (DOMA), which bars federal agencies from recognizing the legal marriages of gay and lesbian couples.

At a press conference held at the 80th annual U.S. Conference of Mayors in Washington D.C., Parker became emotional as she described the hurdles she and her partner, Kathy Hubbard, had to face without the protections of marriage.

“On Monday, my life partner and I celebrated 21 years together. We have a 35-year-old son who was 16 and living on the streets of Houston when he came to our home, because he had been thrown out of his family. We have two adopted daughters, who are now 16 and 21, that we adopted after they spent five years in foster care in the state of Texas. We have had to navigate insurance challenges and custody challenges. One simple change would have made a tremendous difference in the lives of my family and truly the lives of millions of Americans,” Parker told reporters. (The video is embedded in the right panel of this page. Visit our video library for more videos.)