Autism is not a simple disorder to understand. Many high-functioning autistic adults are quite enthusiastic about being part of the workforce, but they often struggle with the question of whether or not they should disclose their condition to an employer.
Many autistics worry that they'll be judged incapable or somehow "defective" by an uneducated employer and eventually be shown the door. On the other hand, not telling an employer carries its own consequences in the form of making the job unnecessarily harder.
So, should you tell your employer you're autistic?
Absolutely -- but only if your autism somehow affects your ability to do your job without reasonable accommodations. Why is this important? For two reasons. First, you don't need to tell your employer everything about your condition. He or she only needs to know the aspects of your disorder that need to be managed to help you stay functional in the workplace. Second, you can't find out what accommodations are available -- or get access to them -- without asking.
How do you approach your employer about your condition?
Identify what is most important for your employer to know and focus on that, not necessarily the autism. For example, if you have difficulty reading social cues, tell your employer that and ask if you can be assigned to a job that doesn't put you in direct contact with the public if you find that difficult to handle.
Similarly, if you suffer from noise sensitivity, ask your employer if there's a way that you can wear headphones at work. Explain that the random bits of noise make it hard for you to concentrate and the headphones -- with white noise, music, or nothing at all -- help you focus. Or, if you simply have an auditory processing disorder that makes it difficult for you to follow verbal instructions, say so. Ask your employer to write down tasks or directions for you to follow.
Why else is it important to disclose your condition?
If you don't tell your employer about your condition, you aren't taking advantage of the legal protections afforded someone with autism against discrimination. Your employer doesn't have to accommodate you or take your autism into consideration when deciding whether or not to retain you -- unless he or she is aware of your condition. That alone is a very good reason to step forward.