BBC Inside Science

The episode examines the US Defence Secretary Pete Hegseth’s plan to screen military personnel aged 30 and over for testosterone deficiency and offer voluntary hormone replacement therapy to those with low levels. It considers whether the policy would improve military readiness, as intended, or whether increasing testosterone is an overly simplistic response with potential drawbacks.

The programme also covers newly observed orca behaviour, with animals reportedly swimming into a dead sunfish hard enough to make it burst, possibly as play or a lesson for younger whales. Its final segment discusses artificial intelligence and mathematics, including AI’s role in disproving a conjecture that had stood for 87 years.