Must you have a reason?

Movies have their ways of passing across thought provoking messages to any viewer. The last movie I saw was a Korean drama and I learnt a great deal in every scene I watched.

There was a particular scene that touched my heart, l was close to tears, one of the characters said

He was going through a hard time right from birth because his step mother depised him for harmlessly mocking her barrenness. He was an only child of the family and the son of the second wife. So his step mom saw his birth as a mockery against her infertility. Mysteriously he was poisoned and survived the ill fate and lost his real mom at a tender age. He went through thick and thin, took his step mom as his real mother. Deep within the woman was hypocritical about her affections until she opened up to him and expressed her displeasure over his existence and openly told him she was behind his poisoning in the past. For a sec, I thought the young man will devastatingly react in a negative way but he said

For a mother
Why would a son need a reason to forgive her?
And,
For a son
Why should a mother need a reason to protect him?

The woman was mute for hours, strucked by the emotional persuasion in his words to win her heart convincing her that it's not by birth motherhood is determined.

What do you think? Are you barren and can't bare children, can you tell me how motherhood without an issue feels like?