Zoe Strimpel asks the seemingly simple question 'what is a woman', but finds no simple answer as she explores the question through a brief history of feminist thought.

She explores the ongoing controversy over trans women in women's competitive sport, and the reluctance of public figures to define what a woman is. while revealing her own views on the issue.

"As the history of feminism itself makes clear, gender and sex are genuinely complicated. That overconfident or oversimplified definitions of woman - which apparently we're all supposed to be able to produce - can be limiting and crude. Not just in relation to trans women but biological women too," she writes.

She continues: "The bitter debate about trans women versus women is a debate about the meaning and realness of biology. And yes, biological difference matters, sometimes hugely. It is certainly real. But there is room for nuance: indeed, there is a necessity for it. Without it, I fear a relapse into arguing that women are defined by their biology beyond the swimming pool or the cycling track or the locker room."

Producer: Sheila Cook