They say having a twin influences your life, for as long as you live, but a new study suggests that females with a male co-twin score higher on mental rotation task than females with a female co-twin.

Mental rotation tasks are tests that require rotation of three-dimensional objects in mental space.

The study revealed that females with exposure to higher levels of prenatal testosterone might perform better than females with lower levels of testosterone.

"If prenatal masculinization does occur in female twins from opposite-sex pairs, it would be expected to be most evident in behaviours that are related to testosterone levels and show a large and robust male advantage, such as the mental rotation task," said Eero Vuoksimaa from the University of Helsinki.

They compared mental rotation task scores between twins from same-sex and opposite-sex pairs and found that females with a male co-twin scored higher than did females with a female co-twin.

Vuoksimaa and colleagues noted that it is unclear if differences in performance are due to prenatal exposure to testosterone or due to their tendency to engage in more male-typical activities.

"More research is needed to disentangle the origins of the masculinization of mental rotation performance in females with a male co-twin," Vuoksimaa concluded.

The study is published in Psychological Science. (ANI)