Looking for sister, born 3-5-64 in Natick adopted - right after

I am looking for my sister who was adopted in 1964 and was born March 5, 1964. Mother lived in Natick at the time, and that is the town listed on the birth record. The babies' Birth name was Beth Ann. Our Mothers' name is Carole Ann (Fournier) Burdwood. She has since remarried, but that is the names listed on the certificate that I have. The Father listed is Roger Burdwood (my father) but he says that that was for legal purposes as they were not divorced yet. I was born in 1961 myself... this was a relationship she had after they were separated after I was born. ;) Also if anyone has any ideas on how I can pursue my search... and MA rules (which I have heard are tricky) I would appreciae it!! Thanks! PJ