Here is some thoughts.
Is your medicine cabinet locked? Over the counter medications locked up?
How about where you store things like Clorox, drain cleaners, ammonia, etc?
Check out the deaths from accidental poisoning. Careless people manage to kill kids all the time. I know way to much about it. My wife is a children's attorney for abused and negligent kids. I don't want to see any kid get hurt. But, built in locks on guns really don't prevent much.
The CDC says 74 and the AP said 113 children died in 2014 from accidental gun shot. Many of them where teenagers messing around with guns. Locked guns may have prevented a few true. But, those left unlocked wouldn't stop anything. Careless adults, lack of discipline and lack of gun safety education cause way more than lack of locks.
Over 400 children under 5 die every year from accidental poisoning. Aspirin ingestion is one of the leading causes. Thats just the ones under 5. Think about it.
About 350 kids under 15 drown every year in swimming pools, about 45 kids under 4 drown in bath tubs every year.
About 180 kids under 15 are killed by cars backing over them in driveways every year.
Lets fix stupid adults first. A gun lock doesn't fix careless and stupid
Requiring a back ground check before people are allowed to have kids would do WAY MORE.