Need help! My real sister has fallen in love with me! I don't know what to do!?

you both need therapy because if a child is born to you two, there's a high chance it will be born with mental problems or other deformities. Are you willing to bring a child of into your life? Do you both a favor and have her move out immediately and change the locks, anyone over 18 and out on their own needs to socialize and be independent, what you are doing is enabling her, not giving her a chance to stand on her own. What if some night during one of her drinking bouts she mentions to someone who knows mom or dad and tells them everything? Drinking leads to stupid things, believe me I have made enough mistakes while drinking. There is no sympathy to a man who takes advantage of his sister while she is so vulnerable so be a man and do whats right. Heaven help any relation or even a girl who gets serious with you if she should find out..What a slap in the face,,,