Openly gay Wisconsin Representative Tammy Baldwin is considering a run for the U.S. Senate seat now occupied by Senator Herb Kohl (D-WI). If she won the election, Baldwin would become the first openly gay member of the Senate.

Seventy-six-year old Kohl announced Friday that he will not seek reelection to a fifth term in the U.S. Senate, saying that it's "time for someone else to serve."

Baldwin is "very likely" to run for the seat, according to the Gay & Lesbian Victory Fund, which has endorsed Baldwin repeatedly.

"This would be a remarkable milestone for LGBT Americans," said Chuck Wolfe, president and CEO of the Gay & Lesbian Victory Fund. "Congresswoman Baldwin is one of the most admired public officials I know. She would have the strong support of those who want to see our economy work for all Americans, and who believe that all voices deserve a place at the table."

Baldwin became the first openly gay candidate to win election to the U.S. Congress as a freshman in 1998.

Three other openly gay lawmakers also serve in the House: David Cicilline (D-RI), Barney Frank (D-MA) and Jared Polis (D-CO).