A special feature in this week’s New Scientist reviews progress towards the creation of eggs and sperm from embryonic stem cells. In the short term, it’s unlikely, despite headline-grabbing stories about the birth of mice from artificial sperm. But in the long term, it’s clearly possible, especially as many groups around the world are working on producing fertile eggs and sperm.
The social implications could be immense, especially for infertile couples. Artificially produced eggs would mean more choice, says the New Scientist. “A limitless supply of eggs could be used to produce hundreds of embryos for any one couple, making it feasible for would-be parents to use genetic screening to choose several desirable traits as well as ensuring embryos are free from disease- causing mutations.” It would also be possible for gay and lesbian couples to have their own genetically related children (although lesbians could not have boys.)
Progress is slow. So far, few artificial eggs have developed far after fertilisation. “Oocytes are very sensitive cells and it doesn’t take much to send them off the rails,” says Alan Trounson, of Monash University. “Getting them to mature and undergo meiosis is a big hurdle.” Mice have been born from artificial sperm, but these were poor swimmers and had to be injected into the eggs. All of the resulting mice died within five months and all of them had serious health problems.
As with IVF, the problem seems to be imprinting. In vitro, the imprinting process is disrupted, leading to the death of the embryo or serious abnormalities. However, says the magazine, “many in the field now think it is only a matter of time before the first child conceived with a lab-grown sperm or egg is born.”
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