For a child born in England in 2011-2012, the chances of being placed for adoption by the age of five varies starkly by local authority, research suggests.
For a child in Southampton, which had the highest rate, almost one in 50 children was put up for adoption.
For a child in Greenwich, an authority with similar socioeconomic profile, it was less than one in 600.
The findings come from Freedom of Information inquiries carried out by Professor Andy Bilson of the University of Central Lancashire, and shared with the BBC and the Bureau of Investigative Journalism.
He focussed on two year groups of children, those born in 2011-12 and those born 2006-7, asking detailed questions about child protection.
Adoption is intended to take children out of care, because their chances of stability and success in education, and life, are better. But in the 20 authorities where adoption rose over five years, the number of children in care had risen as well.