I have several handguns, carbines, and shotguns at home with kids. Each weapon has a Masterlock trigger lock that would be very difficult to remove. I do have one lever action .44 mag carbine that I have removed the bolt and stored in a different part of the house. The handguns are also locked up in a metal tool box that I use as a shooting box. I took both of my kids out when they were about 11 and taught them how to fire and respect all weapons. My oldest daughter (16) is a great shot but only likes to use my .22 and thinks Australian gun control is great. My 14 year old son likes to shoot and believes gun control is hitting your target with the first shot.
I had him on the range one day when he was 12, he was shooting a .22 carbine while I used the .44. He want to try the .44 so I said ok. That thing rocked him back from the bench rest, I thought he learned his leason and would want the .22 back, instead he asked if he shoot a box of ammo? It's now his favorite next to my .30 carbine. Last fall we were shooting shotguns, he a 20 guage and I was using a 12, and he asked if he could try the 12. Well, after 3 rounds of 3" magnum slugs he gave it back to me and said "I think I'll stick with the 20, that thing kicks!" He has never asked to use it again.
If you want a handgun, I would recommend a revolver (.38 Speacial or better) for a casual shooter. An auto (.40 S&W or better, 9mm is marginal)is good if you practice often. The revolver usually has better intrinsic aim, if you have a miss fire all you need to do is pull the trigger for the next round instead of racking the slide to eject the bad round, you don't have to wonder if you chambered a round when you inserted the mag as you squeeze the trigger at a bad guy, nor do you have to remember to take the safety off in the heat of a moment. The downside is that military autos are designed to work in dirty conditions where revolver may not and the revolver usually has only 5 to 6 rounds in the weapon. Autos can carry lots of ammo and usually are quicker to reload. By the same token, if I need more than 5 rounds, I was very out numbered or I should have spent more time on the range.
I recently saw two young guys on the range with Berretta 9MM's (Gov. type) shooting at the old Dillinger type targets at the 7 meter line. The targets after 50 rounds looked like a bad day with a shotgun. Only about 7 rounds hit kill zones, all the rest were scattered around the edges. They gave me some funny looks when I brought my targets back from the 15 meter mark, I had 15 rounds from my S&W Model 60 (.38 Special with 2" barrel, 5 shot) all within 3 inches of the bullseye. They were shaking their heads when they say the next target with 10 rounds of rapid fire all within 6" of the 10 ring. I agreed with them, I needed more practice, the farthest round was twice as far from the 10 ring as it should have been.
What ever weapon you decide on, PRACTICE OFTEN!
Personal carry choises: Conceled: S&W Model 60 Cheif's Special (.38, 2 " barrel, 5 rounds 125gr Nylock hollow points, light, small but marginal)
Open carry: Ruger Speed Six .357 Magnum, 2 3/4" barrel, 6 rounds of 158gr hollow points (light & powerfull, but kicks like a mule, can also be used for conceled carry)
Home defense: .30 carbine with 30 round clip with 110gr hollow point ammo - simple design, short overall length, makes a great club if they try to grab the barrel
Karl