Imagine your street 20 years from now. Who might be living next to you? It could be a lesbian couple and their biological daughter - created when an egg of one of the women was fertilised with the synthetic sperm made from the skin cells of the other. The family on the other side may have a healthy boy, created in the test tube when sperm from the father was inserted into an artificial egg created from the skin of the mother. This is not as far-fetched as it may seem. Scientists have worked out how to make "artificial" germline...