1. The Francis Crick Institute 1 Human Embryo and Stem Cell Laboratory , , 1 Midland Road, London NW1 1AT , UK
2. Royal Veterinary College 2 Department of Comparative Biomedical Sciences , , Hawkshead Campus, Potters Bar AL9 7TA , UK
3. Research Group Reproduction and Genetics, Vrije Universiteit Brussel 3 , 1090 Brussels , Belgium
4. Vrije Universiteit Brussel 4 Department of Reproduction and Immunology , , 1090 Brussels, Belgium
5. The Centre for Trophoblast Research 5 , Department of Physiology, Development and Neuroscience , , Cambridge CB2 3EG , UK
6. University of Cambridge 5 , Department of Physiology, Development and Neuroscience , , Cambridge CB2 3EG , UK
7. Hewitt Fertility Centre, Liverpool Women's Hospital 6 , Liverpool, L8 7SS , UK
8. Bourn Hall Clinic, Bourn 7 , Cambridge CB23 2TN , UK
9. Brussels IVF, UZ-Brussel 8 , 1090 Brussels, Belgium
10. Wellcome Trust – Medical Research Council Stem Cell Institute, University of Cambridge, Jeffrey Cheah Biomedical Centre 9 , Puddicombe Way, Cambridge CB2 0AW , UK
11. Babraham Institute 10 Epigenetics Programme , , Cambridge CB22 3AT , UK