SUPPORT for the role of chromosomes and hormones in sex and gender comes from the David Reimer case study. After a botched circumcision when he was around 7 months old, a psychiatrist (Dr Money) convinced his parents to raise him instead as a girl “Brenda”. However, when he reached puberty and the hormones in his body were causing the expected male changes, they were forced to tell him the truth and he immediately went back to living as a man.