There is an ongoing public debate about sex, gender and identity that is often quite heated. This is an edited transcript of an informal lecture I recorded in 2019 to serve as a friendly guide to these complex issues. It represents my best attempt, not to score political points for any particular side, but to give an introductory map of the territory so that you can think for yourself, investigate further, and reach your own conclusions about such controversial questions as ‘What does mean to be a man or a woman?’