The range of reproductive options has steadily widened. AID (artificial insemination by donor, which dates back to the 19th century) and IVF (in vitro fertilisation, first used in the 1970s) have become everyday techniques. So has ICSI, intracytoplasmic sperm injection, in which a sperm cell is physically inserted into an egg, bringing fatherhood to otherwise infertile men. Last year another practice was added—mitochondrial transplantation or, as the headlines would have it, three-parent children. The world may soon face the possibility of eggs and sperm made from putative parents’ body cells (probably their skin) rather than in their ovaries and testes.