It is only in recent decades that persons with disabilities were finally seen as full persons, complete with sexual desires and needs. We still have a strong strand of Puritanical thought in our culture, though, that often relegates disabled persons to strange asexuality against their will. Every person will at one point or another have a brush with disability, whether that's a short term issue like a broken arm or a longer term disability that effects their entire lives. Either you or someone you love will experience disability; that doesn't mean you can't fuck though!
Disabled people can be sexual, just like abled persons. It just may take more work, effort, and accomodations.