William Schoolcraft
The Modern Laboratory · People
The Modern Laboratory
William Schoolcraft
A Denver doctor who opened his clinic to a laboratory scientist, and helped make day five transfer everyday IVF.
Training. William Schoolcraft completed his medical training at the University of Kansas. He finished his residency in obstetrics and gynaecology at UCLA in 1983 and began practising in Denver the same year. He then trained in infertility at UCLA under David Meldrum, one of the early IVF doctors in the United States. In 1987 he founded the Colorado Center for Reproductive Medicine.
A clinic and a laboratory. In 1997 David Gardner joined him as scientific director, bringing new culture methods from Australia, and Michelle Lane came too. Their 1998 paper showed that growing embryos to the blastocyst stage and transferring them on day five raised the chance of each embryo implanting. Fewer embryos needed to be transferred. In 1999 Schoolcraft, Gardner, Meldrum and colleagues compared blastocyst transfer across two IVF programmes, to see what helped and what did not.
A shared language. With Gardner he described a simple way to grade a blastocyst, with a number for its growth and two letters for its two groups of cells, such as “4AA”. In 2000 they showed that this score was linked to implantation and pregnancy, a step towards transferring a single blastocyst. The grading system is still used in laboratories around the world.
Freezing and testing. His team also worked on preserving blastocysts. In 1999 Lane, Schoolcraft and Gardner reported vitrifying mouse and human blastocysts in a tiny loop without a container. In 2010 Schoolcraft and colleagues reported testing every chromosome in cells taken from blastocysts, before choosing which embryo to transfer.
Still at work. He is certified as a high complexity clinical laboratory director by the American Board of Bioanalysis, unusual for a physician. He has written two books and many scientific papers, and was still publishing research in 2025 and 2026.
Also see: David Gardner, Michelle Lane
About the sources
- Colorado Center for Reproductive Medicine, physician biography: William Schoolcraft (ccrmivf.com): University of Kansas; UCLA residency 1983; fellowship under David Meldrum; HCLD certification; two books.
- Post Hill Press, author page: William Schoolcraft, M.D., HCLD (posthillpress.com): private practice in Denver from 1983; clinic established 1987.
- Surrey ES, Katz-Jaffe M, Kondapalli LA, Schoolcraft WB, Makloski R. Prolonged oral GnRH-antagonist administration before euploid embryo transfer. Reproductive BioMedicine Online 2025 (PubMed 41092830).
- Schoolcraft WB, Fragouli E, Stevens J, Munné S, Katz-Jaffe MG, Wells D. Clinical application of comprehensive chromosomal screening at the blastocyst stage. Fertility and Sterility 2010;94(5):1700–1706.
- Gardner DK, Lane M, Stevens J, Schlenker T, Schoolcraft WB. Blastocyst score affects implantation and pregnancy outcome: towards a single blastocyst transfer. Fertility and Sterility 2000;73(6):1155–1158.
- Lane M, Schoolcraft WB, Gardner DK. Vitrification of mouse and human blastocysts using a novel cryoloop container-less technique. Fertility and Sterility 1999;72(6):1073–1078.
- Schoolcraft WB, Gardner DK, Lane M, Schlenker T, Hamilton F, Meldrum DR. Blastocyst culture and transfer: analysis of results and parameters affecting outcome in two in vitro fertilization programs. Fertility and Sterility 1999;72(4):604–609.
- Gardner DK, Schoolcraft WB. In vitro culture of human blastocysts. In: Jansen R, Mortimer D, eds. Towards Reproductive Certainty. Parthenon, 1999:378–388 (as cited in Room 3).
- Gardner DK, Vella P, Lane M, Wagley L, Schlenker T, Schoolcraft WB. Culture and transfer of human blastocysts increases implantation rates and reduces the need for multiple embryo transfers. Fertility and Sterility 1998;69(1):84–88.
- Encyclopedia of Australian Science and Innovation: Gardner, David Kenneth (Scientific Director, Colorado Center for Reproductive Medicine, 1997 to 2007).
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Compiled with AI-assisted research and checked against the original sources. Not yet peer-reviewed. Corrections are warmly welcomed.
