I have been thinking about a similar idea!
If there was a sudden effect that feminized a fraction of boys and thus the majority of the population's children would go though female puberty. Society would be feminized by sheer numbers, its media, politics, sexuality, where, men in they're rarity will be idealized. Porn will be overwhelmingly cock-centric, where the feminine viewer would prefer to identify with the female participant, though preferably without a vagina. If shemale-male porn could come to represent the majority of porn, then perhaps sexuality in general. The shemale could replace the gg as the desired mate in society. The vagina could become synonymous with surrogacy, as anal penetration becomes standard. Also phalloplasty surgery could become popular with gg