Charles Ellicott Commentary Leviticus 12:5

"But if she bear a maid-child, then she shall be unclean two weeks, as in her impurity; and she shall continue in the blood of [her] purifying threescore and six days." — Leviticus 12:5 (ASV)

But if she bear a maid child. —Better, but if she gives birth to a female child .

As in her separation. —Better, as in the time of her monthly courses . In the case of a daughter, the days of purification in both stages are exactly double that prescribed at the birth of a son. The reason for this difference is probably owing to the fact that the ancients believed that the physical derangement of the system is far greater at the birth of a girl than at the birth of a boy, and that it requires a longer time for the effects to pass away. Similar laws existed among other nations of antiquity and exist to this day among many Eastern tribes.

The Greeks held that a man who had been near a woman in childbirth defiled the altar if he approached it. One of the means adopted during the Peloponnesian War for purifying the island of Delos was to prohibit women from undergoing their confinement on the island. Hindus go so far as to regard all the relatives of a newborn child as impure; the father has to undergo purification rites, and the mother remains unclean until the tenth day, when the child receives its name. Among the Arabs, the mother continues unclean for forty days.

In the blood of her purifying. —Better, in the blood of purification, that is, pure blood. (See Leviticus 12:4.) The law here legislates only for ordinary cases and makes no mention of cases involving twins.

The administrators of the law during the Second Temple, therefore, had to supplement the Mosaic legislation in this instance, as in many other points. They therefore enacted that if a mother had twins, a boy and a girl, the two stages of her uncleanness were those for a girl. If one of the twins was a boy and the other sexless or bisexual, she continued unclean for both male and female. If, on the contrary, one was a female and the other of neither sex or bisexual, her separation was only for a female.