Sex and D&D: Making alien babies

It's what it's all about

"I don't understand - what does
'plant your seed' mean in your land?"

Almost all human history, politics, art, science, and behaviour is shaped by reproduction - how we do it, how it works, who decides. So I was thinking that if we change those things we almost inevitably start to approach a much more genuinely alien race. So, here’s a set of ideas to change the demi-humans.

Dwarves

• Dwarves do not reproduce biologically. Dwarven clerics use secret rituals to make new dwarves in huge stone pots. If these are destroyed, the tribe is effectively doomed to extinction unless new ones are made, and it’s very very hard to make them.
• Young dwarves (i.e., under 30) do not have beards and are sometimes mistaken for females.
• All dwarves have penises, which are for waste excretion only.

Gnomes

• Gnomes also do not reproduce biologically, but are dug out of geodes in metamorphic rocks.
• Most of gnome society is devoted to finding seams of these geodes.

Kobolds

• Kobolds (evil gnomes) also breed using these same geodes. 
• They have a process which converts the geode's contents into kobolds instead of gnomes. The process uses silver and they prize this metal higher than any other.
• They also preserve the stones rather than "hatching" them immediately in the way that gnomes do. The stockpiles of geodes has lead outsiders to believe that kobolds are oviparous.
• The geodes are saved for when new silver or gem seams are found and the tribal leaders want more labour. Kobold children - "scamps" - can work usefully from the age of two.

Elves

• Female elves have a gestation period of about two weeks, at the end of which they secrete a small seed which must be planted and tended for about a year before the child emerges in the form of a pixie.
• This form is retained for about two years before it finds a hollow in a tree and forms a cocoon. The following spring the child elf is born “for real”.
• Adult elves take no part in raising a child until it reaches the age of 20, at which point the pixies take the young elf to meet its parents (or wider family).
• Half elves born of human mothers grow like a human child.
• The dark elves of the high boreal forests with their snow-white skin and raven-black hair breed only in the winter and their children take the form of and are raised by goblins.

Halflings

• Halflings are much like humans except for a shorter gestation period of only three months, during which time the mother is said to be “eating for four”.
• Fertility rates are low, with twins being exceptional and most births being separated by 5-12 years.
• Halfling children mature slowly.

The more I think about these changes, the wider the ripples become. Dwarves are rooted to the place where their pots are; gnomes are nomadic; elves protect their woods as a matter of life or death; halflings are stay-at-homes. All common tropes, but with an underpinning beyond "because".