05-02-2003, 01:04 PM
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#1 (permalink)
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Registered User
Location: Somewhere in Ohio
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Human eggs created by male embryos?
LINKY
Quote:
Scientists can make human eggs from male embryos
By Roger Highfield, Science Editor
(Filed: 02/05/2003)
The ability to make an endless supply of human eggs for post-menopausal women - even for men - could emerge from a breakthrough in reproductive science published today.
Scientists have found a way to mass produce eggs from embryos, even male embryos, a technique that could scrap the "biological clock" of women, end the shortage of eggs for infertility treatments and remove one of the reasons given by maverick doctors for cloning babies.
However, the American research also makes it feasible for men to make eggs too so that it will be possible, in theory, for a homosexual male couple to have children that are genetically their own, with the help of a surrogate mother.
Although it seems likely a similar approach could also help infertile men to make sperm, the technique will not enable women to make sperm because they lack a Y chromosome, the "maleness" chromosome (men do have one X chromosome, the sex chromosome possessed by women, so they can make eggs).
One professor of theology called the work "a cannon ball fired across the bow of Christian bioethics. Many still operate with the assumption that babies require a mummy and a daddy."
Prof Ian Wilmut, of the Roslin Institute, near Edinburgh, is excited by the implications for cloning because it undermines claims that it could be justified for infertility treatments.
"If the method can be adapted for use with human embryo stem cells, and to produce sperm from embryonic stem cells, this would be the end to calls that cloning should be used to overcome infertility," he said yesterday.
Instead, cloning would be used to create an embryo from an infertile person and then an egg or sperm as required, which in turn could be used for IVF treatments.
"In this way, both man and woman would contribute their genes to the child as they do normally," he said. The possibilities are raised today by Prof Hans Scholer's team at the University of Philadelphia which removed cells from early male and female mouse embryos, placed those stem cells in Petri dishes and grew them into eggs and then into embryos.
Reported in the journal Science, the work shows that, even outside the body, embryonic stem cells remain "totipotent," that is capable of generating any of the body's tissues, said Prof Scholer.
"Most scientists have thought it impossible to grow gametes (egg and sperm cells) from stem cells outside the body since earlier efforts have yielded only somatic (body) cells."
But his team found that not only can stem cells from mouse embryos produce eggs but also those eggs can then divide, recruit adjacent cells to form structures similar to the sacs - follicles - that surround and nurture natural mouse eggs and develop into embryos.
The American team now plans to test whether those eggs can be fertilised.
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