I am a female what is the reason for having a hightened sex drive?

Many reasons.: A healthy libidio is normal for both men and women, and is influenced by many factors. The primary influence is neurohormonal, especially levels of androgenic hormones like testosterone. There is evidence that sexual desire is increased around age 30 for women, and can be correlated with the menstrual cycle. Many psychological & physical factors have influence as well.

Need more info: Are you speaking of yourself? Is this a change? How recent? When you say heightened, do mean more sensuous, more sexually responsive, more easily aroused? Has anything else recently changed in your life? Are you taking medications or other substances? Does this happen only w/ specific people or does it happen in many situations? Is this a problem or has it increased your enjoyment?