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I think that perhaps <a href="http://www.abc.net.au/science/articles/2012/02/27/3440547.htm" target="_blank">this</a> could have far-reaching implications.<br><br>
Basically it says that the limitations on ovum production, after menopause, are not, as previously thought, due to a limited supply of ova, maintained alive, since the woman was an embryo (before birth she had many millions), but rather, a limited ability to convert ova stem cells into ova, past a certain stage of development, past menopause.<br><br>
the article says that women were thought to have been given a "bank account" of ova at birth, but that is an over-simplification. In fact, women have even more ova before they are born, than they have at birth. By time they are born, the number has dwindled quite a lot. As they get older, the number gets even lower. It was known for sure that by puberty, they had even less, and by menopause they had none. What this experiment suggests is that it is not the number of ova that is fixed, at puberty (at about 40 x 12), but that it is the number of months (about 40*12), of conversion of ova stem cells into ova, that is "fixed," due to tissue chemistry in the ovary (sort of like developing into a mature ecosystem). And that it may be possible to extend the number of months by fiddling with tissue chemistry.<br><br>
Of course the cytologists did not really "create" ova from stem cells. The culivated stem cells in a manner that allowed them to develop into ova, and in a manner that enabled the cytologists to observe that this microscopic activity was taking place. The manner being implantation of human ovary tissue into mice, who I would assume needed to be immunosuppressed in order to prevent them from killing off the human tissue. And by tagging the stem cells with genes that caused them, and their ova offspring, to fluoresce (probably by implanting genes into the stem cells from a life form that fluorseses).<br><br>
What far-reaching implications? 80-year old women could have biological offspring. Though it seems unlikely, perhaps even deliver babies themselves, if stem cell tissue is removed, cultivated in mice so as produce ova, and then the ova are re-implanted in the fallopian tube, ready to get fertilized by sperm cells from a man of any age. But if that is thought to be risky, their egg cells could be implanted in the fallopian tubes of younger women.
 
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