>>509200528Ah, well, see, you just invoked my personal lore dump!
Gobbos, or goblin girls, are not actually born from goblins.
See, goblins practice parasitic reproduction. Their semen modifies the reproductive system of their human (and elf, dwarf, or whatever race they happen to capture) to produce more male goblin offspring. It also causes their body to release eggs at a vastly accelerated rate, leading to litters of 6-12 goblin pups.
Women who are rescued and return to human society do not return to normal are generally left barren, their bodies forced into what essentially amounts to early menopause from being a forced birthing factory. If they're rescued soon enough, however, they may still be viable, but their reproductive system is already tainted and transformed to accommodate goblins.
From there male embryos all miscarry without fail. Female embyros do have a chance of remaining viable to term, however. The resulting baby is what grows to become a gobbo girl.
Gobbo girl babies resemble normal human children afflicted with dwarfism, up until puberty. At puberty the traits instilled from their mother's tainted womb start to manifest as their skin gradually turns green, their hips widen, and their ears grow out to points. The high survivability of gobbo girls through childhood is owed to this delayed development of inhuman traits. If the mothers gave birth to a tiny green child it would likely be killed on the spot, especially having already suffered as a brood mother for male gobbos.