What is the wisdom behind the 'aqiqah being two sheep for a male and one sheep for a female, and is one sheep sufficient for a male if one is unable to slaughter two?

Among the wisdoms behind the Sunnah of two sheep for the Aqiqah of a male child is the preference for the male over the female. This is one manifestation of that preference, similar to her right in inheritance being half of his. This is the legislation of the All-Wise, All-Knowing: "He is not questioned concerning what He does, but they will be questioned." (21:23) Another manifestation of this preference is that all messengers were men.

However, one sheep is sufficient for the Aqiqah of a male, based on the saying of the Prophet, peace and blessings be upon him: "With the boy is an Aqiqah," and he performed the Aqiqah for Hasan and Husayn with one sheep each.