"...one in twenty women in Japan in 1974 were childless. Moreover, Shaw found that this ratio had increased to one in four by 1977."

That must be a typo.

"...one in thirty women were childless in Italy in 1974. According to Shaw, the rate of childlessness also skyrocketed there by 1977, reaching one in five women..."

Was there a war I wasn't told about? Assuming a complete replacement of women didn't happen in three years, where did all the childless women come from? All those women with children either ceased to exist, or all their kids died, in three years. That just makes no sense.

Thanks!