Assalaamu alaykum. I got my answer, but I read in Behesti Johor that if a son touches his step-mother with lust, then the son's father and step-mother's relation will be haram forever. Is that true? If a son touches his biological mother with lust, does that ruin the son's father and mother's relation? I was born muslim. Please give me the answer according to Islam and Imam Abu Hanifa.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.

This issue is based on a general principle in the Hanafi School of Fiqh, namely, that lustful touching establishes the prohibition of marriage (between the man and the woman's female descendants and ascendants and between the woman and the man's male descendants and ascendants). As-Sarakhsi wrote, "Just as the prohibition of marriage is established by sexual intercourse (i.e. whoever has sexual intercourse with a woman, her female descendants and ascendants become unlawful to him, and this woman becomes unlawful to his male descendants and ascendants as well), it is also established in case of lustful touching and kissing regardless of whether the woman was his wife or slave girl or not..." [Al-Mabsoot]

Hence, if a man touches a woman with lust, her female descendants and ascendants become unlawful to him, and she becomes unlawful to his male descendants and ascendants as well. This includes the examples that you have mentioned in the question. The father's wife becomes unlawful to the father, and the mother becomes unlawful to the father. If the husband touches his wife's mother with lust, then his wife becomes unlawful to him.

The majority of the scholars held a different opinion (that lustful touching does not establish the prohibition of marriage). The opinion of the majority of the scholars is the preponderant opinion in this regard.

Allaah knows best.