Human rights activists say the move will rein in the military's abuses, which have sharply increased with the army's deployment against criminal gangs operating in Mexico.
Brazil on Thursday became the sixth country in Latin America, in addition to Mexico City, to extend rights to gay and lesbian couples but stopped short of legalizing gay marriage.
Mexico's Supreme Court upheld a law Monday that allows gay couples in the capital to adopt children. The gay adoption decision comes a week after the court upheld the constitutionality of gay marriage.
The controversial case has been watched closely by the rest of the country, and may push other states to liberalize their own abortion laws.