Anna and Mike Peterson recently had dinner at their favorite steakhouse, came home, checked on their teenagers watching TV in the basement and then retired to their bedroom -- where Ms. Peterson lit a candle 'to create an intimate atmosphere.'

The next morning, Mr. Peterson left early for work. When his wife woke up, she texted him: 'Good morning, my love. How are you today? I had a wonderful night with you. I hope we can find time for that more often.'

Mr. Peterson responded immediately with exactly one word: 'Busy.'

Do men and women speak the same language?

A University of Pennsylvania study of brain scans has reignited the controversy over what might explain the differences in the social behavior of men and women, and why they often have so much trouble communicating. The findings, published earlier this month in the journal Proceedings of the National Academy of Sciences, indicate that, starting in adolescence, brain wiring starts to differ in men and women. Brain scans of women showed more connections between the two hemispheres, left and right, compared with men of the same age, whose scans showed more connections within hemispheres.

Neuroscientists say the study lends visual support to an idea many have long believed -- that women, in general, may be better wired for multitasking and analytical thought, which require coordination of activity in both hemispheres. Men may be better wired for focused linear tasks that require attention to one thing at a time.

Experts caution the conclusions are speculative, and these patterns show up only when a large number of people are studied.

Other research, though, holds the differences between men and women are a matter of degree, not of kind. There are no categorical differences between the sexes in areas such as sexual attitudes and behaviors, personality and social orientation (whether men are more aggressive or women more caring, for example), according to a re-analysis of 13 studies on the psychological characteristics of men and women published earlier this year in The Journal of Personality and Social Psychology.

'Men and women are much more similar than they are fundamentally different,' says Harry T. Reis, a researcher on the study and professor of psychology at the University of Rochester.

Yet men and women often express themselves in what can seem like predictably different ways. 'Women put their emotional state into speech much faster,' says Louann Brizendine, a neuropsychiatrist at the University of California, San Francisco, and author of the books 'The Female Brain' and 'The Male Brain.' 'That can be overwhelming to men,' she says.

Men and women both feel emotions deeply but process them at different speeds. And individuals vary. 'From what we know of brain circuitry, 10% of each gender behaves more like the other gender,' Dr. Brizendine says.

The research suggests men are more comfortable with linear thinking while women don't mind toggling between topics. They each gravitate to different issues. Women are often encouraged to attend to emotions from a young age, and they like to talk about relationships. Men typically don't like relationship talk as much. In both instances, nurture reinforces nature, Dr. Brizendine says.

If after an argument many women would say they remain upset longer than their husbands, it may be because estrogen enhances and prolongs the secretion of the stress hormone cortisol, which can stay elevated for up to 24 hours, according to Marianne Legato, a cardiologist and founder of the Partnership for Gender-Specific Medicine at New York's Columbia University Medical Center. 'This makes women keep obsessing, stay awake and stay anxious, long after he's forgotten the unpleasant incident,' she says.