Anna Paulina Luna wrote in a letter that she was leaving the House Freedom Caucus over their stance on her efforts to let new parents vote by proxy.

Luna co-sponsored a bipartisan measure to allow new parents in Congress to vote remotely around the birth of their child. Some conservatives are trying to stop it.

Nine House Republicans joined all 213 Democrats Tuesday to keep alive a bill that would allow lawmakers who are new parents to cast proxy votes for three months after their child’s birth.