Alan Handyside
The Modern Laboratory · People
The Modern Laboratory
Alan Handyside
He learned to read the genes of a single cell taken from an embryo, and so began genetic testing in IVF.
A mouse embryologist first. Alan Handyside began by studying how the early mouse embryo sorts its cells into the inner cell mass and the outer layer. His first papers, in the late 1970s, asked when the inside cells become committed to their fate. In 1984 he described a quick way to stain the inner and outer cells of a mouse blastocyst in two colours. In 1987 he was among the authors who used cultured stem cells to make mouse embryos lacking the enzyme missing in Lesch-Nyhan syndrome.
At Hammersmith. At the Institute of Obstetrics and Gynaecology at Hammersmith Hospital in London he joined Robert Winston's team. In 1989, with Kate Hardy and Winston, he used his two-colour staining to count the cells of human blastocysts grown in culture.
The first tested embryos. He then took on a harder question. Could one cell, removed from an embryo, tell parents what they needed to know? For two couples at risk of passing on serious conditions that affect boys, his team removed a single cell from each embryo at the six to eight cell stage. They copied a stretch of DNA found only on the Y chromosome to learn whether each embryo was a girl or a boy, and transferred only girls. The first pregnancies came in 1989, and in April 1990 Nature reported that both mothers were carrying twin girls. In 1992 the team reported the birth of a healthy girl after her parents, both carriers of cystic fibrosis, had their embryos tested for the condition itself. For families who had watched a child suffer, it offered a different future.
A long career. He was the first chairman of the European Society of Human Reproduction and Embryology's special interest group in reproductive genetics, and a cofounder and first chairman of its PGD Consortium. In 2010 he and colleagues described karyomapping, which reads patterns inherited from both parents across the whole genome of an embryo. He has been a visiting professor at the University of Leeds and an honorary professor in reproductive genetics at the University of Kent. In 2009 he shared the Gabbay Award in biotechnology and medicine. He was still publishing on embryo testing in 2026.
Room 4, Day five, Room 5, Testing an embryo
Also see: Robert Winston, Kate Hardy, Henry Leese, David Whittingham
About the sources
- Handyside AH, Horak J, Gimenez C, et al. Preimplantation genetic testing for meiotic aneuploidy in trophectoderm biopsies: is it time to change our approach? Reproductive BioMedicine Online 2026;52(5):105504. PubMed 41865500 (evidence of current activity).
- Shaikly V. The origins of preimplantation genetic testing. Progress Educational Trust, 22 December 2025.
- University of Kent, School of Biosciences. Professor Alan Handyside, Honorary Professor in Reproductive Genetics: staff profile (last updated 22 March 2022).
- Seminars in Reproductive Medicine 2012;30(4):253–254. Guest editor introduction with biographical note on Alan H. Handyside (ESHRE roles, Leeds visiting professorship).
- Brandeis University. Pioneers in assisted human reproduction will receive Gabbay Award Nov. 16. BrandeisNOW, November 2009.
- Handyside AH, Harton GL, Mariani B, et al. Karyomapping: a universal method for genome wide analysis of genetic disease based on mapping crossovers between parental haplotypes. Journal of Medical Genetics 2010;47(10):651–658. PubMed 19858130.
- Handyside AH, Lesko JG, Tarín JJ, Winston RM, Hughes MR. Birth of a normal girl after in vitro fertilization and preimplantation diagnostic testing for cystic fibrosis. New England Journal of Medicine 1992;327(13):905–909. PubMed 1381054.
- Handyside AH, Kontogianni EH, Hardy K, Winston RM. Pregnancies from biopsied human preimplantation embryos sexed by Y-specific DNA amplification. Nature 1990;344(6268):768–770. PubMed 2330030.
- Hardy K, Handyside AH, Winston RM. The human blastocyst: cell number, death and allocation during late preimplantation development in vitro. Development 1989;107(3):597–604. PubMed 2612378.
- Hooper M, Hardy K, Handyside A, Hunter S, Monk M. HPRT-deficient (Lesch-Nyhan) mouse embryos derived from germline colonization by cultured cells. Nature 1987;326(6110):292–295. PubMed 3821905.
- Handyside AH, Hunter S. A rapid procedure for visualising the inner cell mass and trophectoderm nuclei of mouse blastocysts in situ using polynucleotide-specific fluorochromes. Journal of Experimental Zoology 1984;231(3):429–434. PubMed 6209359.
- Handyside AH. Time of commitment of inside cells isolated from preimplantation mouse embryos. Journal of Embryology and Experimental Morphology 1978;45:37–53. PubMed 353216.
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Compiled with AI-assisted research and checked against the original sources. Not yet peer-reviewed. Corrections are warmly welcomed.
