When Ontario opened its adoption records June 1, adult adoptees yearning for information about their birth parents applied in droves.

But as the replies came back, it became clear something was missing: The names of their fathers.

From all the 250,000 Ontario adoption registrations, less than 10 per cent have fathers’ names on them, according to the Ministry of Government Services.

Ruth Rideout was devastated by the omission. The 61-year-old adoptee received her statement of birth in October and found the father’s section of the form blank, with a line drawn through it. “He is half of my biological makeup and I need to know if there are any illnesses, conditions,” she says.

Rideout’s birth mother recently died at age 81. It turns out legislation prohibited her mother from naming him.

Until the mid-1980s, an unmarried woman could not put her baby’s father’s name on the statement of birth unless she and the father made a statutory declaration that he be named, according to the Vital Statistics Act. The child was “illegitimate,” a word that was not removed from the act until 1981.

But when unmarried women filled out the father’s section anyway, it seems the information was removed — whited out, blacked out or covered up.

Mothers interviewed by the Toronto Star say they remember putting the names of their children’s fathers on birth registration forms they filled out in hospitals many years ago.