Male Adoptee 1958 Louise Wise Adoption Agency last name possibly Mittendorf

I am helping my father begin the search for his birth mother. He was adopted through the Louise Wise agency, we are in the process of requesting information from them. From what we know his mother was unwed and the father was married to another woman. His birthday is May 29, 1958 and he was born in Staten Island according to his adoptive parents. Also one of the birth parent's last names may have been Mittendorf(or something similar to Mittendorf). He has very very blue eyes and black hair. Any information would be helpful. Thanks!