GEN147 Procreation is a primary aim of sexual relations. The biblical command of procreation [this verse] is fulfilled with the birth of a boy and a girl Yevamot 61b. However, a husband’s sexual obligation continues in force even after the requirement of procreation has been met. Judaism does not sanction birth control by means of interrupted coitus Genesis 38:9-10.  The use of contraceptives, tampons, or oral sterilizing drugs by pregnant or lactating women is permissible, if it is needed to prevent conception which may endanger the life of the mother or her offspring Yevamot 12b. Men may not use contraceptives. Continence is the only permissible birth-control method, providing it is practiced with the consent of the wife and that the minimal requirement of procreation has been fulfilled. Childlessness is a painful problem which confronts some couples. Modern science has achieved remarkable progress in alleviating that condition Prevailing rabbinical opinion sanctions artificial insemination, using the husband’s semen but not the semen of another donor. Test-tube fertilization with the husband’s sperm of a human egg taken from the woman’s ovary is permissible. The embryo may be reimplanted in the mother’s womb. Some rabbis object to this procedure on moral grounds. The implantation of a fertilized egg into the womb of a host mother raises a problem of maternal identity. According to one opinion, if the embryo is forty days and older, the child is the offspring of the biological mother. According to another opinion, the woman who experiences the labor and travail of childbirth is regarded as the mother. There is as yet no consensus on the moral aspect of surrogate mothers. A similar problem regarding parental identity is raised in connection with the transplant of an ovary or testicles. Except for the problem, there seems to be no objection on moral or ethical grounds.  BLOCH 225