The study, released Thursday, compares how same-sex and different-sex couples divide chores and child care responsibilities, and how these decisions impact their lives at work and at home. The results suggest that gender plays a significant role: While 74% of same-sex couples share routine child care responsibilities, only 38% of different-sex couples do so. A similar divide appears in caring for a sick child: 62% versus 32%.

“It wasn’t that if you took gender out of the picture, it was all 50-50,” says Ken Matos, lead author of the study and senior director of research at the Families and Work Institute. “But the way different-sex couples divide labor seems to be a bit more restrictive and tied to gender.”

The research rings true to Abby Corbett, 34, a litigation partner at law firm Stearns Weaver Miller in Miami, in the way she and her wife Danielle run their home. “It’s pretty egalitarian in our house,” Corbett says. “When Danielle was pregnant with our daughter, and when she stayed home for a year and a half, she did all the household stuff because she was home. I just paid the bills. Now that she went back to work and I’m actually pregnant, we shifted the balance a bit, where I took over more household responsibilities.”

Currently, Abby pays the bills, handles paperwork, and does the laundry; Danielle irons, cooks, and grocery shops. Abby gets their 3-year-old daughter up and drops her off at preschool so that Danielle, 38, can go in early to her job in aviation safety at the Federal Aviation Administration.

“Danielle leaves work early, so she gets the whole afternoon with her,” Corbett says. “The nighttime routine we do together. We put her to bed, and we each read her a book.”

When they decided to begin a family, the two women agreed that Danielle would leave her job as a corporate-jet pilot and find work that didn’t involve regularly being out of town. Neither has family locally to help with emergencies, and there are occasions—maybe 20% of the time—when Abby has zero flexibility because she has to be in court or in a deposition.

“My job is very flexible except when it’s not at all flexible,” Abby says. “One of our careers had to give a little bit, and it made more sense that the pilot’s job had to take more of a hit in adjusting.”

Now, when something comes up during the workday, Abby tries to cover whenever she can, since she knows there will be times that she can’t. “I’m sort of banking it,” she says. Compared with straight couples, their division of duties “is more negotiated, and there are less assumptions about who does what. It’s not: ‘You’re the mom so you’re going to pick her up.’ ”

The Families and Work Institute study also found that couples who talked about who would do household chores were more satisfied than those who never had the conversation, but wanted to. Women were more likely to want to discuss it but held their tongues: 20% of the women in the different-sex group of couples studied and 15% of the same-sex group, as compared to 11% of the men in either group. “The most important thing is to be able to say what you’re looking for and to encourage your partner to speak freely,” Matos says.

The study surveyed 225 two-career couples with a median age of 40, of whom a third had children under 18 living at home. The researchers found that among different-sex couples, gender roles, work hours, and income level correlated with the type of chores performed. “Women tended to take responsibility for cooking and cleaning; men tended to take responsibility for outdoor work and repairs,” Matos says. “The person who earned the most did the man stuff; the person who earned the least did the woman stuff.”

But that didn’t hold true for same-sex couples, who were more likely to share responsibility or cross gender norms in assigning primary responsibility for a task.

“There’s no preconceived gender roles with same-sex parents. You end up talking about everything more because there’s zero assumptions,” says Seth M. Rosen, 41, a nonprofit consultant in New York City, who divides child care equally with his husband Jacob K. Goertz, 41, an emergency room physician with Beth Israel Hospital.

Moreover, the process of adopting a child involves a home study, counseling, and lots of questions about child care and work. “Gay couples generally have to do a lot of planning to have a child, and I wonder if that plays into it,” Rosen says. “You are forced to think about a lot of the issues really early on.”

The month before their daughter, Sarah, was born last year, Rosen left his job as the managing director of communications and development at advocacy group Gay Men’s Health Crisis because of the hours required and evening work. “I didn’t think it was possible to do that job and be the kind of parent I wanted to be, at least for the first two years,” he says.

If Sarah has to go home sick from daycare on a day Rosen is working, Goertz will pick her up unless he’s doing clinical work. If Goertz can’t leave the ER, Rosen will get her. “It works really well,” Rosen says.

Similarly, Brett and Matt Cloninger-West tag-team their daily child care—with realtor Brett dropping off 1-year-old daughter Libby at daycare and business analyst Matt picking up—while handling emergencies based on their respective work schedules. “Nighttime awakenings and periods of sickness are juggled between both of us and partly influenced by what each of us need to be ready for the next day,” says Brett.