[Ancesthntr]

What happens if my doctor asks if I own any guns (he won’t) and I lie and tell him no? Is it now illegal to lie to a doctor?

You're not under oath, and he's not a law enforcement official, so you have no legal obligation to tell him the truth. I will tell the doc "no," be polite, pay the bill and never use said doc again. Smart-ass answers will get you put on the list, and I don't want to make it any easier for the statists to do what they'd like.

However, I've never been asked about this issue by a doc before.

[newgeezer]

[your doctor is] not a law enforcement official

Not so fast.

In 1998:

... the Supreme Court ruled that a single false statement to a federal agent, including a simple "no" to an accusation, can be punished as a crime.

The law makes it a crime to utter "any false statement" to a federal agent, and "the word 'no' in response to a question assuredly makes a 'statement,'" said Justice Antonin Scalia for the 7-2 majority.

(excerpt from The Los Angeles Times)

I'd like to think you're correct. But, I don't know how the law is worded and, technically, anyone acting with the authority of the federal government could be considered a "federal agent."

These are perilous times. Those who favor dismantling (rather than repealing) the Second Amendment would be wise to consider that, in doing so, they’re inviting similar unlawful erosion of our First and Fourth Amendment rights in the foreseeable future. If they think that can’t happen, they don’t know human nature, history, and why the Bill of Rights was ratified in the first place.