Training in genetics in Edinburgh in the 1950s led to a PhD on the developmental biology of mouse embryos with unusual chromosomal complements. Fundamental aspects of reproduction under study included ovulation induction, oocyte maturation and embryonic growth to blastocysts. It led to the introduction of embryo stem cells, preimplantation genetic diagnosis, the exact timing of human oocyte maturation in vitro and studies on fertilising human eggs in vitro to alleviate human infertility. My work was helped by studies on sperm capacitation and the physiology of fertilization in domestic and laboratory species by Thibault, Dauzier, Austin, Chang, Yanagimachi and others. I met Charles Thibault at a meeting in Cambridge U.K. where he criticised the work of Moricard, and then frequently on lecture circuits. Impressed by his grandeur but not his doubts about human IVF, Steptoe and I initiated human embryo transfers and the birth of Louise Brown. Details of her pregnancy had to be confidential to reduce the risks of abortion associated with the intrusion of numerous newsmen chasing the story. I was compelled to withold this information at a meeting in Paris in the late 1960s when I had to leave early to return to UK. This omission annoyed Thibault and led to our celebrated quarrel. I felt he failed to appreciate the complexity, the implications of this pregnancy and an astonishing future. So much was at stake, including IVF, stem cells and preimplantation diagnosis to help millions of patients. Some months later, our dispute was ended even if somewhat formally. Nevertheless it is a pleasure to recall how we shared so much in common. I still admire him as an inspiration to many colleagues and students, and a father figure in French agricultural research.