Anne Laura McLaren 26 April 1927 7 July 2007 First published in , 10 July 2007 http://www.theguardian.com/science/2007/jul/10/uk.obituaries Reproduced with permission of The Guardian Dame Anne McLaren, who has died aged 80 in a car accident while travelling with her former husband from to , was one of Britain's leading scientists in the fields of mammalian reproductive and developmental biology and genetics.

Her research in the basic science underlying the treatment of infertility helped develop several human-assisted reproduction techniques. Her work also helped further recognition of the importance of stem cells in the treatment of human disease. As she put it, she was interested in "everything involved in getting from one generation to the next". Both of these areas raise serious ethical issues, and Anne was a leading contributor to the debates in the UK needed to develop acceptable public policy regulating them. Among her many honours, she was the first woman to hold office as vice-president and foreign secretary in the more than 300-year-old Royal Society.

Anne was the daughter of Henry McLaren, 2nd Baron Aberconway, and Christabel McNaughten. The family had homes in London and Bodnant, north Wales, and she gained a zoology degree at Lady Margaret Hall, Oxford. During postgraduate years at Oxford, she worked under JBS Haldane, and Kingsley Sanders, and in 1952 obtained her DPhil.

The topic of her thesis concerned murine neurotropic viruses, which she studied under Sanders, and in the same year that she obtained her doctorate she married Donald Michie. They then worked together at University College London (1952-55) and at the , London (1955-59). During this period they were interested in the versus nurture problem, studying the effect of the maternal environment in mice on the number of lumbar vertebrae.

This work led them to take an interest in the technique of embryo transfer and implantation, and in collaboration with me, in showing it was possible to culture mouse embryos in a test tube and obtain live young after placing them in the uterus of a surrogate mother. In 1959 Anne and Donald were divorced, although they both moved to Edinburgh. Anne continued her work on mammalian fertility, embryo transfer techniques, immunocontraception and the mixing of early embryos to form chimeras (organisms consisting of two or more genetically different kinds of tissue) at the Institute of Animal Genetics. Her book on chimeras, published in 1976, is a classic in the field.

In 1974 she became the director of the Medical Research Council mammalian development unit at University College London. It was there that she developed her enduring interest in the development differentiation of mammalian primordial germ cells. She wrote another classic book, this time on Germ Cells and Soma, in 1980. After retirement from the Medical Research Council in 1992, she became principal research associate at the Welcome Trust/Cancer Research UK in Cambridge, a position she held at the time of her death. During her career she was an author of more than 300 papers.

Many of the areas in which Anne worked are associated with serious ethical issues. One of her principal contributions was as a member of the Warnock Committee, which produced a white paper that played a major role in the passage of the 1987 Family Law Reform Act and the 1990 Human Fertilisation and Embryology Act. The latter established the Human Fertilisation and Embryology Authority, on which Anne served for 10 years. More recently she had been participating in the discussions on