Both Honey and pumpkin are mostly used by women, especially pumpkin. Both of them are almost exclusively used to refer to people you have a very close relationship, such as family/romantic.
Pumpkin is used to refer to young children, although it can be used longer for girls. A mother could call either sex of children by this name. As stated earlier it is used mostly by older people now adays as it probably originated
on farms and more people lived or were born on farms then in cities as little as 70 years ago. Also I have never heard it used romantically, it seems to me to be exclusively for children.
"Pumpkin" is usually used to very small children, boys and girls, by a close relative. ©