How can I convince a doctor to let me have a vasectomy?

I am male, 25 years old. I never want to have children. Neither does my wife. She is 22. We have been married for 3 years now. We married each other because we both knew from the beginning that we never wanted children. I have aspergers/nld (a learning disability) which runs in my family. I never want to be a dad. EVER. But I am very worried that doctors will reject me for being too young and for not having any children. So can anyone out there who has been through this give me suggestions or advice?? Any guys my age or younger and childless who have had vasectomies??? Do I have to lie and tell the doctor I have 5 kids already LOL ???? Thanks!