Is another 'aqiqah obligatory for twins if the mother was pregnant with them, and what is the ruling on 'aqiqah if the newborn is male or female?

The Sunnah is for the 'Aqiqah for a boy to be two sheep, and for a girl, one sheep. One sheep is sufficient for a boy. If twins are born, the Sunnah is for an 'Aqiqah to be offered for each of them separately. One 'Aqiqah is not sufficient for both of them, by agreement of the people of knowledge.