Martha McCarthy is a Canadian lawyer who has represented same-sex couples who have changed the definition of marriage in Ontario and the Yukon. McCarthy passed the Bar in Ontario in 1991, winning the Silver Medal and the Family Law and Advocacy Prizes, and has practiced family law since then. She was counsel for M. in M. v. H., which, after eight years and a decision from the Supreme Court of Canada, resulted in widespread amendments to include gays and lesbians as spouses in both federal and provincial legislation. In 2000, she commenced the equal marriage case Halpern, which resulted in the first decision in the country and internationally calling for immediate same-sex marriage, effective June 10, 2003. Martha later acted for the Hendricks couple in Quebec, and the Dunbar couple in the