Crying in front of someone you're interested in romantically is a sure way of putting him off. At least that's what the latest research by Israeli neuroscientists from the Weizmann Institute suggests.
Why? Because tears, say the scientists, contain subtle chemical signals that makes women appear less attractive to men.
Writing in the journal Science the experts describe tests involving 24 men who were given either tears or saline solution to smell. First of all it was confirmed that the volunteers couldn't tell the difference between the real and the fake tears (as both are odourless). But when the men had to judge photos of women based on how attractive they thought they were, 17 out of 24 rated them less attractive after sniffing real tears than after sniffing the salt water.
The tests even involved measuring the volunteers' testosterone levels - as testosterone is a hormone involved in male sexual arousal - with the results coming to a similar conclusion (that is, the men sniffing the real tears had lower levels of testosterone than those sniffing salt water).
But it's not just any old tears that dampen desire. Apparently only tears produced by emotions contain the passion-killing chemical - if your eyes water because you're chopping an onion or because you've got something in your eye, your tears just don't have the same effect.
The experts suggest their findings may explain the real purpose of tears - to put men off.
There again the bloodshot eyes, runny nose and blotchy skin that go hand in hand with a good cry could have something to do with it.