A review into the role of social workers in adoptions, commissioned by BASW, criticised the current practice of denying children close contact with their birth families.
The review, carried out by academics at the University of Huddersfield and Royal Holloway University of London, said that severing ties with birth families can have a detrimental effect on children's emotional wellbeing and can lead to identity issues.
"Adopted children denied contact can experience serious identity issues and when they are free to seek out their birth families at age 18, adoptive parents can be ill-prepared for the emotional consequences," states the review.
On the back of the findings BASW is calling for a rethink of adoption law to consider a more open approach to contact between children and birth families.
The organisation has also questioned whether keeping adopted children apart from their birth families is practical given widespread internet access.
In its response to the review, BASW states that it will, "call for a review of adoption law in all countries of the UK into whether the assumptions about severance of connection to families of origin is ethical".
BASW said it wants national and local politicians to evaluate the effectiveness of current adoption policies, "with a consideration of whether and in what circumstances a more open approach to maintaining kinship links should be promoted in legislation and policy".
However, Brid Featherstone, professor of social work at the University of Huddersfield, who led the review, suggested that instead of legislative change a cultural shift among social workers is needed.
"You should start from the assumption that direct contact with birth parents ought to be considered," she said.
"Usually, adopted children go searching when they get to 18 and it can store up trouble if they haven't had previous contact, enabling them to see their birth parents for good or ill.
"They can stop having fantasies about these wonderful parents that they were stolen away from, or equally that they were absolutely terrible people. It's about their identities. Adopted people told us that identity is a lifelong issue for them. Where do I come from? Who do I belong to?"