писар: son
He had one son and four daughters.
Вақте таваллуд кардани Элисобат фаро расид ва ӯ писаре зоид.
When the time came for Elizabeth to give birth, she gave birth to a son.
Bonus:
Notice in the first sentence that the word daughter, духтар, does not have a plural ending. In Tajik, if a noun follows a number, the noun does not take the plural ending.
Писар can also mean boy.
Some other family members:
модар: mother
падар: father
духтар: daughter
ака: older brother
додар: younger brother
апа: older sister
хоҳар: younger sister
модаркалон, бибӣ: grandmother
парадкалон, бобо: grandfather
набера: grandchild
тағо, амак: uncle
хола, амма: aunt