During the first few years of a male's life, the inside fold of his foreskin is attached to his glans, very much the way the eyelids of a newborn kitten are sealed closed. The tissue that connects these two surfaces dissolves naturally over time - a process that should never be hurried.
The foreskin can be retracted when its inside fold separates from the glans and its opening widens. This usually happens by age 18. Even if the glans and foreskin separate by themselves in infancy, the foreskin still may not be retractable then because the opening of a baby's foreskin may be just large enough to allow for the passage of urine.
