Looking for birth sister born 5/11/1975

I am looking for my birth sister born 5/11/1975 at St. Clair Hospital in Pittsburgh, PA. My mom was 17 years old when she had this baby, and the baby had red hair and was supposedly adopted through a private lawyer to a family who lived in Fox Chapel at the time. I also know that this family adopted a little boy either the same year or the year after. If I could only use the date of birth and hospital to get a name, I'm sure I could find my sister. Any advice? Thanks!