looking for sibling, more info

Looking for a sibling that i recently found out about. I believe birth year around 1945 or 46. Birth mom's first name susan or susie. Do not know male or female. My parents were married at the time but father strayed. Mother from Marion Illinois so most likely gave birth there or surounding area. Last contact made with my family in East St. Louis. Birth father's name was Robert and birth mother stated at the time that she would name the baby the same if a boy. I wish I would have known years ago so I could have searched. I would love to find you and you have 5 other siblings and one deceased. Can anyone help??