Scientists have found that almost half - 47 per cent - of men first glance at a woman's breasts.
A third of the "first fixations" are on the waist and hips, while fewer than 20 per cent look at the woman's face, reports the Daily Mail in UK.
In fact, breasts are not only the first thing men look at, they also glance at them for longer than any other body part, revealed experts.
Many believe that the reason behind such male tendency could be evolutionary, as women with larger chests and slim waists - such as Jennifer Hawkins, Lara Bingle and Rachael Finch - have higher levels of the female hormone oestrogen, indicating greater fertility.
But the researchers conceded that there could be a more prosaic explanation.
"Men may be looking more often at the breasts because they are simply aesthetically pleasing, regardless of the size," the Daily Telegraph quoted them as saying.
Subjects tested by researchers from New Zealand's University of Wellington were presented with six images of the same woman, digitally altered to increase or decrease the size of her bust, waist and hips.
The scientists recorded which areas men looked at first, the number of times they looked, and how long their gaze lasted, using cameras and mirrors to measure tiny eye movements.
"Eighty per cent of first fixations were on the breasts and midriff. Men spent consistently more time looking at the breasts and also made significantly more fixations upon them than other regions," the study concluded.
It also found that men began to gaze at the "components of the hourglass figure" within 0.2 seconds.
The research also discovered that few glances were directed at the arms, lower legs and feet.