Counsellors and advisers who help parents find their children say that until recently it was nearly always mothers who wanted to find the babies they had handed over for adoption; but they believe modern society's increasing emphasis on the fundamental role a father plays in rearing a child has inspired some men to seek their sons and daughters.
Ariel Bruce, a qualified social worker who is one of the leading investigators helping natural parents and adopted children find their families, said: "There is a different currency today about men's importance and the part they play in the family. Men whose children were placed for adoption are moved by that."
The majority of men looking for lost children are in late middle-age or elderly, and fathered them in adoption's heyday, the Fifties and Sixties, when illegitimacy was taboo and abortion illegal. Those who have contacted Miss Bruce include a middle-aged man who never saw his girlfriend again after she was sent thousands of miles away to have their child, and a man who as a teenager was sent to an approved school for making his girlfriend pregnant.
Their search is often more difficult because their names never appeared on any official documents. Birth certificates, for instance, may often have the space for the father's name left blank.
Many fathers in the post-war period were also kept away from pregnant girlfriends by the shamed parents who often arranged for the birth to take place in mother-and-baby homes, away from where the mother-to-be lived. While it was heart-wrenching for the young woman to give up her child, the father often never saw the baby at all - a loss which some ignored, or denied, until late in life.
"These are men who feel that they had no choice or power over the choice made about what happened to their children," said Miss Bruce. "There comes a time for parents when they realise that their child will have reached 18 and the time is coming when that child will be able to try to make contact. By the time the adopted person is in their thirties and nothing happens, parents start to think: 'I could die soon and my child will never know me.'"
Under the existing regulations, parents who give up babies for adoption have no guaranteed means of tracing them, but can register their willingness to be found. Children, however, can be given official information to help them find their parents.
When adoption was at its peak, 35 years ago, about 25,000 babies a year were handed over by their parents. Another man whom Miss Bruce helped is in his fifties and was seeking a child he had fathered when he and his girlfriend were students. After the birth they were kept apart by their families for two years. They met again and married, had more children, but then divorced. Now alone, he mourned the loss of his first- born.
Another father told her he and his girlfriend had been put in homes after it became clear that they had had under-age sex. "He was kept right away from the mother and the child."
Not all the men seeking their children were victims of their parents' disapproval; some behaved badly and have come to regret it. One man who approached Miss Bruce for help confessed he had refused to marry his girlfriend, forced her to give up their child, and insisted on his freedom. Now in his sixties,"he realises what an incredibly devastating thing he had done. He found both the mother and her daughter and it mattered to him so much to apologise".
Other men, said Miss Bruce, were like mothers, who often became concerned about the whereabouts of an adopted child after having another baby. One of her clients came to Britain to search for his adopted child in his forties after he had just fathered another baby. An American, all he knew about his first child was that his girlfriend had been sent to Britain to have it 25 years ago.
Francis Coller, of After Adoption, an information service for those affected by adoption, said that while more fathers were keen to find children, the adopted child was usually keener to meet its mother. "When people have found their mother, it is usually then that they want to find their father. You cannot get away from the fact that the person who matters most to those adopted is the person who gave birth to them, who gave them life. It is the most fundamental thing of all."
The growing trend for fathers to seek out their children coincides with changes in regulations on adoption, which have been brought in to encourage it as a form of childcare after being out of favour for many years. Couples who want to adopt a child will now have the right to appeal if they feel they have been turned down unfairly, or if they were the victims of political correctness.
The Government is bringing in the new measures on 1 April, after a string of controversial cases where parents were denied the right to adopt on the grounds of education, age or race.
Under the new measures, couples will be told when their application is being considered by an adoption panel. They will receive a copy of their assessment report, be able to respond to it in writing, and will be allowed to respond to any rejection. The Secretary of State for Health, Stephen Dorrell, said the changes would remove "fashionable theories" from adoption.