What is the ruling of Islamic law on delaying the aqiqah for a newborn due to financial hardship, and is it permissible to hold a single feast for the aqiqah of two children, a male and a female?

The 'Aqiqah is a confirmed Sunnah, not an obligation, according to the majority of jurists. It is recommended to slaughter two sheep for a boy and one for a girl. However, if one slaughters one sheep for a boy, it is sufficient. Its preferred time is on the seventh day. Slaughtering the 'Aqiqah is better than giving its value in charity. If the amount of money is only sufficient for one sheep, then slaughter it for the newborn girl and leave the boy, because the time for his 'Aqiqah has passed and one is not able to afford it, and "Allah does not burden a soul beyond its capacity."