The transmission of human life, man's supreme capacity to co-create men, that sharing in God's creative power, will be converted into a function of the same physiological, psychological, and moral level as micturition or defecation.» (firstthings.com)
Regarding painful micturition of female children it's commonly due to UTI from infancy till puberty even after! (easybabylife.com)
Other causes should be determined by a specialist my advice is to take your child urgently to doctor when he or she cries during micturition because it's painful condition and for boys circumcision is very good to avoid UTI recurrent attacks. (easybabylife.com)