BRD2 and leukemia: Spermatogonia: number decreased 50% in standard-risk treatment (n=12) and 80% in high-risk treatment including cyclophosphamide (n=9). Without cyclophosphamide, no significant effect on spermatogonia. Leukaemia therapy, even without cyclophosphamide, delayed the initiation of spermatogenesisTesticular volume, FSH, LH, testosterone and inhibin B at end of puberty: normal in standard-risk treatment. Variable compromise in high risk