Growth Rate & Stages
Elves are generally a long lived species with lifespans reaching to the early 1000's. Many in elven culture are not considered adult until they are over 100 years, although in some families that live outside of Elvish society parents may consider their children grown as they enter their 20's.
As Elves are a long lived species reproduction happes rather infrequently. It is said that often times elven females will only be able to get pregnant once a century, with the odd female being able to get pregnant twice in a century. Twins are uncommon among elven families.
Elves are able to procreate with various races, but as a society they tend to look down on these children as "half-breeds" and they will never quite be as good as full blooded elves.