Renesmee Cullen is a vampire/human hybrid, who has the best of both worlds when it comes to her genetics.
Renesmee can sleep and eat food if she wishes, but also does have a thirst for human blood as well.
We know she will grow to adulthood at a rapid speed and continue to keep her youth.
Of course the natural return to Twilight would be through a sequel, continuing the story started by Edward Cullen and Bella Swan through their daughter Renesmee’s golden eyes.