Muslims! . 'Baptism' is practiced by Christians, just once in their life time while in childhood, because-?

"However we don't do it in childhood, because we say every child is born clean and sinless. But upon reaching adulthood."...Actually, some Christian denominations believe the same. Do not believe in "inherited sin". Believe that we are born innocent and free of sin. And believe that baptism should be done only when one is old enough to know right from wrong and make a more mature and knowledgeable commitment to one's belief/faith.