When a Jewish mother gives birth, even if it is a live birth, she becomes Tamei – spiritually disconnected. It is the actual birthing itself which renders her Tamei. The subsequent duration of her impure state depends on the gender of her child.
Childbirth constitutes growth and further development of Hashem’s world. Moreover it is the fulfillment of the very first Mitzvah of the Torah. One would hardly expect that this would bring about a diminishing spirituality.
In similar vein we find that procreating itself conveys Tumah on the engaged parties. (This level of Tumah forbids us to cross the Western Wall.) Shouldn’t construction of the world be something positive, and have a connection with heightened purity?
Before we answer this question let’s introduce a passage from the Talmud regarding the evil desire for idolatry and forbidden relationships. I paraphrase:
The Sages tried to eradicate the evil desire for idolatry, which was too great for the people to overcome. They ordered a fast of three days and three nights, whereupon the desire for idolatry was surrendered to them.
The Sages further said: Let us pray to remove the temptation for forbidden relationships. They prayed for mercy, and he was handed over to them.
He said to them: “Realize that if you kill me, the world goes down”.
They performed a trial by imprisoning him. After three days they saw that without him the world would not be populated,so they put out his eyes and let him go.
In essence the Yetzer Horah lectured the Sages, that there is a price to pay for eliminating the temptation for illicit interaction. The powers of good and evil are equally balanced in the world. You can eradicate the temptation for prohibited relationships, but with it, will be weakened the desire for permitted relationships.
What we see from here, is that without a hint of desire, or a trace of temptation, the world would not function and continue producing. We are not angels and cannot act purely for the sake of heaven without any personal consideration. We may therefore suggest, that is why Tumah is contracted on the engagement in procreating, both in the marital act and the subsequent childbirth.
It is virtually impossible do something completely right or completely wrong. But we have discretion on the ratio of good to evil.
Rabban Yochanan ben Zakkai was once riding a donkey leaving the city of Jerusalem. He passed a young woman who was picking barley from the dung of Arabian animals. “Rabbi,” she said “Please help me, I have nothing.”
Rabban Yochanan responded “My daugther, who are you?”
“I am the daughter of Nakdimon ben Gurion” she replied.
“If so, what happened to your father’s money?” Asked Rabban Yochanan, for Nakdimon ben Gurion had been one of the richest men in the city. Rabban Yochanan recalled reading her Kesubah which stated that her dowry had been one million gold coins, with additional support from her father-in-law, who was similarly wealthy.
“He was not scrupulous enough in giving Tzedakah and therefore lost his blessings,” was the reply.
Asks the Talmud, but everyone knew of Nakdimon ben Gurion’s charity. When he would walk from his house to the Beis Hamedrash, his servants used to lay woven wool mats before him, so that he did not have to step food on the ground. After he walked over the rugs, they were left for the poor.
Answers the Talmud, since there was an element of glory seeking in the charity, his Tzedakah did not shield his children from poverty. The taint is his performance removed the protection that accompanies the Mitzvah.
Utensils purchased from a non-Jew, that one intends to use on Shabbos, should be immersed in a Mikve, before Shabbos.