The female of the human species has a vagina, covered with labia, a clitoris which is sensative to touch. She carries her ovaries, fallopian tubes and her uterus inside her body. Most every person who has seen the female body unclothed is aware of the external differences.
The woman when she is born has. already in existence, all the cells that will mature into ovum (eggs) in her ovaries. That means they only have to mature to be release into a fallopian tube where they may be fertilized and changed into a zygote. If the zygote gets to the uterus and implants there, it becomes a embryo and nine months later a baby.
These cells mature into ovum and one is released during each menstrual cycle. This means a woman feels little reproductive pressure and thus generally does not seek sex as much or as often as do the males.
One thing that can make a woman seek sex is the desire to reproduce in sync with her most fertile period of the menstrual cycle.