Personally wouldn't care much. Didn't have a father, blood or not, raising me when I was little.
Grandfather was around but he didn't do much raising. I always suspected who my family calls my biological father to not be my real one anyway because of blood type issues (apparently both parents are O and I'm A+ but I'm definitely my Mother's child) but it doesn't matter. I have no father listed on my birth certificate and I was actually raised by my grandmother, aunt and personal experiences.
Grandfather was around but he didn't do much raising. I always suspected who my family calls my biological father to not be my real one anyway because of blood type issues (apparently both parents are O and I'm A+ but I'm definitely my Mother's child) but it doesn't matter. I have no father listed on my birth certificate and I was actually raised by my grandmother, aunt and personal experiences.