Professor Hely Tuorila of the University of Helsinki, Finland, says her experiment with twins shows that about half of the preference for sweet foods is genetic.
That's about the same level of inheritability as asthma, or some personality traits. Asthma is part genetic, part environmental trigger.
Tuorila believes a sweet tooth developed as an evolutionary pre-historic mechanism to guide humans to nutritious foods, like carrots or apples.
But it's gone haywire with all the sugary foods and drinks we have today.
Tuorila has published four research papers establishing the genetic link, however, she says her team doesn't know WHICH genes are responsible.
She is quick to say genetics aren't an excuse to eat too many sweets.
It's an urge we have to learn to control.