Nicola Sturgeon has argued for a wider debate on teenagers' rights, as she defended plans to allow 16-year-olds to change their legal gender in Scotland. Each society settles on its own thresholds to determine when a person is old enough to make informed decisions about matters including voting, having sex or drinking alcohol. This is a collective agreement about the legal point at which human beings reach maturity. But what is human maturity in moral terms? Aristotle warned against trusting the judgments of the young, saying, “they have exalted notions, because they have not been humbled by life or learned its necessary limitations”. Meanwhile, psychological studies suggest that the period of adolescence among Gen Z has extended – ‘25 is the new 18’ – which means that ‘adult’ roles and responsibilities now occur later than in they once did. All this is evidence, according to some, that teenagers’ judgments are less likely to be sound than their elders, and rather than expecting them to be political beings, we should allow them to be kids. Conversely, there are those who argue that younger generations have been failed by a system that is rigged to favour the interests of older people; that they should play more of an active role in our democracy because their concerns are the concerns of the future; and that they are more likely to make better judgements about society because they are far more connected to the world and aware of their own values than previous generations. Should we trust children and teenagers to make good judgments about the future? Or, if active citizenship is the preserve of adulthood, what is an adult? Producer: Dan Tierney.