Who gets to compete as a woman in sports?

Olympic gold medallist Caster Semenya, from South Africa, has lost her appeal against proposed rules from track's governing body that require some female runners to lower their naturally high testosterone levels. It's a ruling that's expected to have huge implications on the future of women's sports. Today on Front Burner, Katrina Karkazis helps us understand why. She's a bioethicist who's been studying the regulation of hormone levels in women's elite sports for years.