Legal Question in Family Law in Maryland

If you are the bio father and listed as such on their birth certificates, you probably don't. But otherwise, since (I assume) you weren't married to the mother, you have never legally determined to be their father, and you might have difficulty with such things as school enrollment, medical care, etc. You ought to consider consulting an experienced family attorney with the objective of filing a petition to establish paternity. This would result in your obtaining legal custody.