Are the girl and the boy born with a complete reproductive system[having all the internal and external sex organs present in adult man or woman]? or organs like uterus, fallopian tube, seminal vesicle, prostate gland,vas deference formed after birth?

Define "complete": In one sense all the equipment is in place and finished forming with the exception of some rare birth defects. There are transitions that occur within either gender after birth under hormonal control that finalize egg and sperm readiness that will be complete at puberty. Neither gender is reproductively ready at birth, but what needs to be there is in place.