I am a mother of a 9 year old son, a 18 month old daughter, and a step mom to a 15 year old girl. I have known this girl since she was 4 years old when I met her father. A year later, me and her father had our son. Her mother led her to believe that I will always favor my son over my step daughter. I have had problems with her since then. She used to come over every other weekend and stay with us. I have never treated her different than her brother (my son). Everything changed and got worse three years ago when her mother ended up on drugs and hasn't been seen since.