When she first got into the field in the mid-1970s, Julia Heiman received all manner of responses when she told people she was a sex researcher.

"It varied from people wanting to talk to me for forever and about everything to people being very put off and feeling like that just wasn't the right thing to do, or being embarrassed," recalls Heiman, now director of the famed Kinsey Institute for Research in Sex, Gender and Reproduction at Indiana University in Bloomington. Often, she adds, they asked questions that science could not yet answer.

As a doctoral student at Stony Brook University, she studied the way people physically experience different states of emotion. But as Masters and Johnson published their groundbreaking books on sexual response and dysfunction, she shifted her focus, eventually researching the way treatment for sexual problems can improve relationships inside and outside the bedroom.

She taught at the University of Washington for 23 years; as her career progressed, she found that the most ardent philosophical resistance -- and often the biggest roadblock to research funding -- came from people who "didn't think that something like this should be studied," she says. "They were afraid -- and this is not a silly concern -- that if we studied it, it would some how spoil it."

But her experience has been the opposite. Heiman, now 62, found that "if you did a really careful job of it, it would reveal more complexities and surprises and maybe even challenge ideas that we had."

When she arrived at the Kinsey Institute in 2004, she and her colleagues worked to broaden its research focus. Scientists associated with the lab are now studying stress responses in women with post-partum depression, mistakes made by condom users, the impact condoms have on sexual sensitivity and the way hormone levels vary among women in different parts of the world. Some of the studies add to our general knowledge of human sexuality while others may have immediate applicability. The research on condom sensitivity, for instance, may help manufacturers produce a product more people will be willing to use.

Heiman herself is in the process of publishing results from a multi-year study looking at the relationship satisfaction of men and women from five countries who've been married more than 20 years. In men she found that a number of factors could predict relationship satisfaction, including health, sexual functioning and intimacies like kissing and cuddling. In women, only sexual functioning -- level of desire, frequency of arousal and orgasm -- seemed to predict satisfaction. That, Heiman says, "was really different from what we expected."

The institute is also studying sexually aggressive young men in the hopes that understanding them "might help us propose some new ideas on the prevention of sexual violence."

Sexual violence is among the main areas where Heiman would like to see more research dollars directed. She'd also like to see sex research, which has boomed during her three decades in the field, further our comprehension of how couples form and stay together and the role sex plays in that process.

To this day, people still ask Heiman questions that sex researchers have not yet solved, like what factors shape sexual identity and how sexual activity affects our overall health. "There's a lot more we need to understand," she says.

And if we did understand more, she adds, "I think we'd be better off as a culture and take better care of one another."