I came out thinking that the biological definition is revisionary, so I guess Bettcher did a good job. One point I thought was maybe important is when Bettcher pushes on the "expanded" biological definition, and point that adult=sexual maturity doesn't really match what we usually call a woman. Bogardus replies that by "adult" he means "all around maturity" so that's not an issue. But what "all around maturity" means exactly ? I think one strength of the biological definition is that it's very clear cut ; there's no vagueness, so sociological messiness: you can reproduce then you are an adult. But as I see it bringing this "all around maturity" is going to be make it challenging to build such clean picture and undermines one of the motivation to go with the biological definition in the first place.