Here in Iowa a doe fawn will normally breed if her mother was an mature deer. Fawns usually breed later (2nd rut) so the fawns that they give birth to are born (usually) a month after the mother's first birthday.

Since a fawn usually breeds late, the fawn that it has may be too young or too small in its first fall. A fawn of a fawn is less likely to breed.

Fawns in Iowa usually also have only one fawn themselves, whereas mature does usually have twins or triplets.