I think I argued quite well that a Vulcan three year old is equipped to leave the house, hold down a 9 to 5 and start payments on hir mortgage for a small pleasure moon that should be in the black by the time they're almost 40 when the mating urge gets really specific for the wife and not the secretary bent over a photocopier.
Kes was frakking Neelix when she was one years old, and Kim was frakking her two year old daughter Lynnis, and if that timeline had persisted within a couple months, someone who had been changing Andrew Kim's diapers weeks earlier would be hopelessly romantically in love with him too. On DS9 Alexander looked almost 20, and "someone" on the main cast should have been showing him a good time which should have pissed off his father that a 30 year old genetically engineered human doctor was taking advantage of his 7 year old son.
The differences between Vulcans and Romulans.
Ponfar was either added to make sure that a ridiculously logical species remembered to make babies, or Pon Far was subtracted because a highly emotional sexual species didn't need permission or excuses to rape and kill their neighbours.
Vulcans are reeeeeeally smart. A 4 year old with an IQ of 300 and the mental discipline to excel at telepathy and bind their emotions?
That sounds like something you'd fight a civil war over, determining the shape of your children and the future of the species... Romulans just seem not quite as bright, and they need machines to probe minds. What if the Age of Reason wasn't just an ideological shift, but surgical?