British scientists develop embryos containing genetic material from a man and two women

recently successfully used genetic materialby amaleand twofemales to create human embryos,local media reported recently, a result that could help develop effective treatments for certain geneticdiseasesScientists at the University of Newcastle in the UK are reported to have first bred a pair of fertilized eggs for men and women, but thewomen who used to grow the fertilized eggsthe wrongdoingThe scientists then extracted the nucleus of the fertilized egg and transplanted it into anotherfemaleremoved from the nucleus of the egg, which contained normal mitochondriaUsing this method, scientists eventually created human embryos that "repaired" mitochondrial defects in fertilized eggs, but contained genetic material from amaleand two women, and was therefore described by some as having a "three-parent" embryo with a father and two mothersThe scientists involved in the study stressed that it was inaccurate to refer to such embryos as "three parents" because the vast majority of the genes that determine their characteristics are located in the nucleus The normal mitochondria provided by another woman contain a very limited amount of genes that have no effect on characteristics such as the appearance of the embryo as an adult Mitochondria are found outside the nucleus of cells and contain small amounts of DNA, and DNA in mitochondria is generally passed on only to future generations by the mother If the mother's mitochondrial DNA is defective, it may lead to future generations with epilepsy, stroke, mental retardation and other diseases