i adopted my now 4 y/o son from the foster care system (he was 4months when i got him and 2.5 y/o at adoption) the same day my home study was finished and i was about to go "into the books" for a private agency to adopt baby number 2, dfs called and wanted to know if i wanted my son's 6 week old sister!!
perfect timing! she is now 7 months old and i am anxiosly awaiting tpr and adoption! when i was going through a private agency, i asked for statisits (specific to thier agency) they said that 4 out of the past 26 adoptions done were to single parents. good luck!