Melissa Dahl, who admits she cries “embarrassingly easily,” investigates the question. One reason? Women seem to have shallower tear ducts:
“There are several studies over the years that have shown that men have larger tear ducts in their eyes, so that it is less likely for the tears to well up to the point of spilling over the eyelid onto the cheek,” said Dr. Geoffrey Goodfellow, an associate professor at the Illinois College of Optometry in Chicago. There’s also this paper from the 1960s, in which a physician from the University of Michigan reports how he used male and female skulls to measure the length and depth of tear ducts, finding that women’s were shorter and shallower.
Hormones may also play a role:
[Researcher Ad] Vingerhoets believes [testosterone] inhibits crying. Male prostate cancer patients, for example, tend to become more emotional when treated with medications that lower their testosterone levels.
But this isn’t just about testosterone: Back in the 1980s, biochemist William H. Frey and his team analyzed the chemical makeup of emotional tears and compared them to tears caused by irritants. They found, among other things, that emotional tears tend to contain prolactin, a hormone produced by the pituitary gland that is associated with emotion. … Lauren Bylsma, an associate professor in psychiatry at the University of Pittsburgh who has studied crying with Vingerhoets, said that this difference in prolactin levels “may help explain these differences in crying, as well as other differences in emotional expression and depression vulnerability between men and women.”
Speaking of such differences, Walt Hickey compares men and women when it comes to the movies that make them cry.
The Dish 