"There's a kind of spirit of loving acceptance that is an important part of what children need . . . and that may be in some way subtly undermined by the notion that we can expect a certain amount of tailoring, fine-tuning, on the kids we get," Nelson said.
However, he said, "the difficulty is justifying limits on people's liberties in the name of worrisome possibilities as opposed to demonstrated harm."
Most see a medical value in the technology when used to try to prevent the passage of some 200 sex-linked diseases, such as Duchenne muscular dystrophy and hemophilia, which are transmitted through the female.
But many fear the process could lead to abortion when the preferred sex is not conceived.
The religious community tends to oppose gender selection.
Rabbi David M. Feldman of the Teaneck (N. J.) Jewish Center, a specialist on Jewish law and medicine, says that although pre-selection does not necessarily violate Jewish law, "it doesn't seem to be in the spirit of general acceptance. . . . The idea is to be grateful for children of both genders."