Is he manly? Wait to see the whites of his eyes, American scientists insist

How do we judge manliness and femininity? One way is to look at the whites of people’s eyes, scientists have found.

Called the ‘sclera’, the white is yellower and redder in men, but bluer and greener in women, and we unconsciously notice the difference.

‘People use sclera colour as a cue for making sex-related judgments about faces. It’s not something that people are consciously aware of,’ said study chief Professor Richard Russell from Gettysburg College in Pennsylvania in the US.

Called the ‘sclera’, the white is yellower and redder in men, but bluer and greener in women, and we unconsciously notice the difference

Traditional indicators like soft skin and full lips in women or a chiselled jaw and strong nose in men also play their part.

So in the first experiment of its kind, the team created photo pairs of identical faces with no strong male or female traits.

On changing the sclera colours they found people were much more likely to judge red-yellows tints as masculine and blue-green as feminine.

But the effect wore off with older people, says the research, published in the journal Archives of Sexual Behaviour.

Professor Russell believes this is because less of the sclera is visible as our ageing eyes sag.

On changing the sclera colours they found people were much more likely to judge red-yellows tints as masculine and blue-green as feminine.