The panel rejected arguments that Proposition 8 advanced California's interests in promoting childbearing and ''responsible procreation,'' noting that it had no impact on the rights of same-sex couples in the state to raise children or adopt. Drawing heavily on a 1996 Supreme Court ruling that overturned an antigay initiative in Colorado on equal protection grounds, the panel found the initiative violated the Equal Protection Clause of the Constitution by singling out a minority group and taking away the right to marry, which it already possessed in California, ''without a legitimate reason for doing so.''