A Doubt and Rebuttal

Why is the wife of one's son from suckling prohibited for him for marriage - that is, if she is no longer married to his son from suckling - as the majority of scholars state, although they are not related by blood The answer is the Prophet's statement,

« يَحْرُمُ مِنَ الرَّضَاعِ مَا يَحْرُمُ مِنَ النَّسَب »

(Suckling prohibits what blood relations prohibit.)