They have all the same benefits and responsibilities as traditional opposite-sex couples.
Смотреть больше слов в «Англо-русском универсальном дополнительном практическом словаре И. Мостицкого»
opposite sex: translation the opposite sex the other sex; (from the point of view of a female) males; (from the point of view of a male) females. (Also... смотреть
opposite sex: translation the opposite sex the other sex; (from the point of view of a female) males; (from the point of view of a male) females. (Also... смотреть
n. женский пол (или противоположный пол, если о нем говорит мужчина).
противоположный пол