ABSTRACT
Medical practice involving human embryos involves the assisted reproductive technologies. Initially a woman’s own eggs and her partner’s own sperm were used to create embryos. The first experiments developed the technique of natural cycle in vitro fertilisation (IVF) where the woman’s own natural single dominant follicle yielded only a single egg. Donated embryos could come from embryos surplus to the requirements of other infertile patients or could be created specifically from individually donated sperm or eggs which may or may not have been matched on physical characteristics to the relevant member of the recipient couple. The creation of embryos in IVF depends very much on the predictions for fertility after investigation of a couple. The most important single contributor to prognosis is female age which declines optimally from the age of 31, significantly from the age of 35 and precipitously from the age of 39.
