Is it normal for bisexuals to have a sexual prefence in gender?

I've always considered myself to be bisexual since I was turning into a teenager. Though for some reason my sexual desires were strong for men and for a few months re-questioned my sexuality. Recently, I've obtained a stronger physical attraction for women, before that I've had an emotional attraction. However, my sexual desires for women still aren't as strong as they are for men. I've never really felt like having a serious/romantic relationship with a guy...it kinda gets puts me in a uncomfortable place for some reason and If I were to have sex with a guy, I'd feel more comfortable having nothing more than a friendship...so I don't believe I'm all that biromantic. I'd go all the way in a relationship with a woman though. But I don't get why I'm sexual attracted to men...it's been so confusing at times.