Megan Fox has claimed women automatically have the upper hand over men in relationships because they have a vagina.

The actress made the comment in an interview with Cosmopolitan magazine to promote her forthcoming movie, Jennifer's Body.

When asked about relationships, Fox replied: "Women hold the power because we have the vaginas.

"If you're in a heterosexual relationship and you're a female, you win."

Fox also revealed that she could count on one hand the number of men that she had stripped naked in front of.

"I never call them guys. I always called them boys," she said. "Maybe it’s a superiority complex - my needing to keep them down."

The Transformers star plays back-from-the-dead cheerleader Jennifer Check in Jennifer's Body.

The Matias Anaya-directed film is released later this month.

Ultimate Megan Fox