Half of children waiting for adoption in Scotland are unable to find families willing to take them, it has emerged.
Adoption issues are being examined by the executive
The British Association for Adoption and Fostering (BAAF) said there are between 400 and 600 children needing a home in Scotland at any one time.
The organisation said some children were harder to place than others, but there were also concerns that the system was letting them down.
The Scottish Executive is currently reviewing the law governing adoption to see how the situation can be improved.
The BAAF study also found that one fifth of children in their monthly Scottish newsletter did not receive a single inquiry from interested families.
The charity said children that were harder to place included school age children, brothers and sisters and those with health problems and disabilities.
There are also problems where children have had one or both parents who were drug users or who had been smokers.
BAAF spokesperson Barbara Hudson said: "In the newsletter across the course of the year we would maybe feature upwards of 100 to 150 children and half of these children we don't get inquiries for."
Chairman of the executive's adoption review group Graham Cox said it would be looking at the operation of the adoption agencies and how the process can be speeded up.
"We will look at whether unmarried couples can adopt thus widening the scope for adoption," he told BBC Radio's Good Morning Scotland programme
"We'll be looking at delays, particularly in the courts when adoption petitions are launched.
"We'll be looking to see if the system can be streamlined in order to cut down in the time between the lodging of the petition and the final judgement of the sheriff."
Harriet Dempster, the director of social work with Highland Council and review group member, said it was important to look beyond what can sometimes be challenging behaviour.
"I have spoken to young people who are seeking adoption and they would want to put the other side," she said.
"They very much want to be part of a family, many of these children have got very positive sides to their personalities, to their interests and will respond."