When Obama signed his 23 Executive Orders this morning, #16 was to clarify that Obamacare "does not prohibit doctors [from] asking patients about guns in their homes." Yet it must be understood that even if they ask these questions, they can't compile their answers into a list which they then pass on to the government.
This prohibition comes courtesy of Sen. Majority Leader Harry Reid (D-NV).
When Obamacare was being debated in the Senate in 2010, Reid inserted an amendment that forbids the government from using doctors to compile information for a gun registry.
In fact, the amendment makes it clear that Obamacare cannot be construed to authorize doctors to collect "information relating to the lawful ownership or possession of a firearm or ammunition."
Therefore, even if doctors take today's 16th Executive Order to heart and ask their patients about guns, the answers cannot be used to form some type of gun registry database.