NEW YORK — The secrecy that long shrouded adoption has given way to openness, and only about 5 percent of infant adoptions in the U.S. now take place without some ongoing relationship between birth parent and adoptive family, according to a comprehensive new report.

Based on a survey of 100 adoption agencies, the Evan B. Donaldson Adoption Institute said in a report Wednesday that the new norm is for birth parents considering adoption to meet with prospective adoptive parents and pick the new family for their baby.

Of the roughly 14,000 to 18,000 infant adoptions each year, about 55 percent are fully open, with the parties agreeing to ongoing contact that includes the child, the report said. About 40 percent are “mediated” adoptions in which the adoption agency facilitates periodic exchanges of pictures and letters, but there is typically no direct contact among the parties.

“The degree of openness should be tailored to the preferences of the individual participants,” said Chuck Johnson of the National Council for Adoption, which represents about 60 agencies. “It points to the huge importance of the right people being matched with each other.”

The Donaldson institute, citing its own research and numerous other studies, said most participants find open adoptions a positive experience.

In general, the report said, adoptive families are more satisfied with the adoption process, birthmothers experience less regret and worry, and the adopted children benefit by having access to their birth relatives, as well as to their family and medical histories.

“The good news is that adoption in our country is traveling a road toward greater openness and honesty,” said Adam Pertman, the institute’s executive director. “But this new reality also brings challenges, and there are still widespread myths and misconceptions about open adoption.”

The challenges, according to Pertman and other adoption experts, often involve mismatched expectations as to the degree of post-adoption contact. The Donaldson report recommends counseling and training for all the adults involved, as well as post-adoption services to help them and their children work through any problems that arise.

The president of one of the largest U.S. adoption agencies, Bill Blacquiere of Bethany Christian Services, said his staff encourages expectant birthmothers to meet with the prospective adoptive family to discuss the array of options for an open adoption.

“As much as possible, we allow the parties to design that themselves,” Blacquiere said. “We mediate to make sure both parties are getting what they need.”

The post-adoption relationship may start out warily, then become more comfortable as time passes, but Blacquiere said each party should keep the other’s expectations in mind even as circumstances change.

“For adoptive families, they need to make sure they live up to their commitments, and not try to go back on their initial agreement,” he said.

“On the birth parent side, they need to remember that this isn’t co-parenting – part of their role has to be blessing the new home that their child has.”