Older women have a greater chance of becoming mothers now that scientists have developed a way of replacing the "batteries" in their eggs to make the eggs young again, boosting the women's fertility. British IVF doctors have applied to the Human Fertilisation and Embryology Authority for permission to test the technique on 20 women, perhaps as soon as next year.Unlike men, who continue to produce fresh sperm throughout their life, women are born with all the eggs they will ever have. The eggs age with their host, making it ever harder for a woman to conceive."This could be a real breakthrough," said Professor Charles Kingsland, of the Hewitt Fertility Centre, in Liverpool.Scientists have shown that it is possible to rejuvenate older eggs by, in effect, "changing their batteries". All cells carry power packs called mitochondrial DNA. A type of cell called an "egg precursor cell" holds much younger mitochondrial DNA, which can be harvested and swopped into an older egg, giving it an energy boost. ..