My Beautiful Companions

[Note： This is a story specifically crafted for a male audience, with a male protagonist.]
As a colleger, I stay at my brother’s place. My sister-in-law is both attractive and kind, and every bit of her embodies the type of woman I am drawn to. Being in my adolescence, I have often dreamed of making love to her. Well aware how wrong this is, I have tried to avoid her as much as possible. However, to my utter astonishment, I discovered my brother is impotent, and they have been without marital relations for a long time. She deeply desires a child, and his inability to impregnate her has left her in tears more than once. One night, she came into my bedroom and asked, "Could you help me conceive a baby?" Torn between panic and exhilaration, I couldn’t look her in the eye. What am I supposed to do?