New techniques for genetically manipulating sperm may allow scientists
to circumvent existing laws prohibiting human germline engineering and
reproductive cloning, and increase their technical capabilities.

UK newspapers reported in December that British fertility expert Robert
Winston has obtained a patent on a technique that would allow researchers
to genetically alter the human male germline cells that develop into
sperm. Winston developed the technique in collaboration with researchers
at the Cedars-Sinai Medical Center in Los Angeles and the California
Institute of Technology in Pasadena, and with funds granted by the US
National Institutes of Health. According to Phillip Koeffler of Cedars-
Sinai, "This does provide the capability of making designer babies, and
it will be up to society to decide what to do with it."

A Sunday Times report quotes Dr. David King, editor of GenEthics News
in London, predicting that the technique could create a social gulf by
conferring another advantage on the rich. "The commercial motive will
mean ethical restraints are brushed aside," he said. (Lois Rogers,
"Winston patents technique for 'designer sperm,'" Sunday Times,
12/10/00; Mary Vallis, "Gene-fixing technique can erase bad traits,"
National Post, 12/11/00, <http://www.nationalpost.com/home/
story.html?f=/stories/ 20001211/400643.html>.)

A few weeks later, scientists in Japan announced they had grown sperm
from stem cells derived from cloned mouse embryos, and then implanted
the sperm back into the testes, where they appear normal. The researchers
said that the technique, which they plan to test on humans, will allow
infertile men to produce genetically related offspring. They believe
that they will also be able to produce eggs from "reprogrammed" cells
derived from cloned male embryos, which would allow children to be
produced with genes of two men, rather than of a man and a woman.
(Cherry Norton and Lois Rogers, "Clone scientists can grow sperm in
laboratory," Sunday Times, 12/21/00, <http://www.sunday-times.co.uk/
news/pages/sti/2000/12/31/stifgnfar01003.html>.

With this technique, researchers could genetically manipulate male germ
stem cells, and then screen the sperm into which they develop for defects
before using them to fertilize an egg. Even more than Winston's method,
which involves injecting the sperm precursor cells into testes for the
final stages of maturation, it could encourage those scientists who are
eager to push ahead with human germline engineering.