I've seen a couple of questions that I think I can answer, but I'm not a medical professional, just someone interested in medical sciences who likes to research and read scientific literature. If I meet the reference requirements for what makes a good reference, is it ok if I answer a question even though I'm not a medical professional?
We welcome all contributions. We cannot ascertain your professional credentials in any way anyway.
If the answer is good, then that is all that counts. You seem to have read the relevant parts of the help center and here on meta about reliable resources and what we think would make for a nice, good or great answer (or in fact bad ones as well).
If you meet the quality standards we aim for here then this is a most desirable addition.
The answer has to be a resounding YES, as I find in my case a personal experience with a particular medical condition has caused me to become more knowledgeable about the symptoms, causes, and effective medicines and home remedies than your typical pediatrician. Furthermore, not everyone has access to high quality medical care in all instances, and for some depending on the condition, the internet is the only viable option.
I'm sure others out there who've been dealing with their own health issues have become their own experts, and it is this community of experience that creates value. Yes, I and 99 other users may only be experts in combined 100 different diseases, but when you add it all up it creates a valuable knowledgebase that can complement professional medical diagnosis or even supplant depending on the severity of the condition and access to health care.