Women are naturally attracted to other women?

I am a woman and I never was physically or emotionally attracted to a woman. My sister is a Lesbian, she tells me Lesbianism is an emotional attraction to other women, and I have never felt that. I've always been emotionally attracted to men. I am comfortable with my sister and her partner(s) and lesbian friends. I have briefly wondered about this issue, but I know I have no interest in an intimate relationship with a woman on an emotional or physical level.