"Some girls are bigger than others," Morrissey sang. "Some girls' mothers are bigger than other girls' mothers."
Smiths fans believe that Morrissey was referring to breast size, but the lyric also implies that overall size is strongly influenced by genes. But why are some girls taller than others? One reason is puberty. At sexual maturity in females, there is a wave of sex hormones that closes the epiphyses (the ends of the long bones in our bodies), so that girls who mature late will generally be taller because they have had more time to grow. Short women generally reach puberty earlier than tall women -- whose bodies spend more energy on growing than on entering puberty.
Regardless of the timing of puberty, most men are taller than women. Why is this, in an age where most of us are well-fed and have access to good medical care?