‘Spermageddon’: is male fertility really in crisis?

Recent research has suggested a global reproductive crisis could be
in the offing, with researchers in Israel saying average sperm
counts may have more than halved in the past 40 years. But a study
published last month appears to call this narrative into question.
Ian Sample is joined by the Guardian’s science correspondent Nicola
Davis to unpick why these studies have come to different
conclusions – and what could be causing the crisis, if declines are
as dramatic as they appear. Help support our independent journalism
at theguardian.com/sciencepod