I have been in the midst of  a long trial dealing with the issues of the so called family first policy versus possible bonds with a prior foster family.  Their have been several experts in the case dealing with bonding versus the identity issues with biological family.  This appears to be a cutting edge issues.  The ultimate decision is what is in the child's best interest and there is a legal question of how much weight should be given to kinship versus a bond with a prior none kinship family. 

Originally, the courts and DSS appeared to have a policy not favoring family in practical terms but in the more recent decades DSS( DCF) appeared to have had a policy of always looking for family first so long as the family passes a minimal standard before looking at at alternatives.  The cases are not as clear cut as the policy appears to state.  In fact there are more de facto parents rights that are coming across the court and there is litigation about what a family actually means.