Wondering how your relationship will change when you have kids? Pick up a doll, a new study suggests.

Researchers watched 182 couples in the third trimester of pregnancy playing with a infant-sized doll, and then examined the couples’ interactions with their babies nine months after birth.

Couples who were supportive of each other with the doll tended to be equally positive in their real-life parenting relationship. Those who criticized each other with the doll kept criticizing each other with their babies.

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“Some of the couples were very positive, saying nice things to each other about their parenting. With the doll they might say ‘You’re going to be such a great dad.’ After the birth of the baby, their talk would be very similar: ‘You’re such a natural,’” said Sarah Schoppe-Sullivan, co-author of the study and professor of human sciences at The Ohio State University in a press release.

“We saw the same kinds of behaviors between parents when they were interacting with their baby that we saw a year earlier with the doll.”

The experiment is part of a long-term study called the New Parents Project that is investigating how dual-earner couples adjust to parenting. The researchers are hoping to use the information to develop support tools for parents-to-be.

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“Co-parenting has consistently been linked to child outcomes. When parents fight and undermine each other’s parenting, the child suffers,” said Lead author Lauren Altenburger, a doctoral student in human sciences at Ohio State.

“If we can identify couples who may have problems with their co-parenting before their baby is even born, we may be able to intervene,” she said.

Even if you and your spouse are completely in sync romantically, that doesn’t necessarily translate to parenthood. While the doll experiment showed a link to parenting relationships, the couple’s romantic relationship did not, the researchers noted.