I would just say,
"Because I don't want you at home alone all day."
You really don't have to be specific as to "why," when she questions you. More than likely, anything you say is not going to be good enough, anyway....she wants to stay home alone and is challenging your decision.
A 12-year-old should NOT be left home alone - you are absolutely right and doing the correct thing.
Do not let her constant questions erode your confidence as a parent! You're her mother and you have her best interests at heart.
When she demands an answer, just say,
"It's a SAFETY ISSUE."
Just tell her that you do not want her at home alone, because of safety issues and that you are NOT going to change your mind. Any reasons you offer, she will only try to pick apart.
You really don't have to justify your decision.
She's not going to like it, BUT OH WELL, you're her mother and you're looking out for her. She doesn't have to like it.
Just the fact that the neighbor's son is home alone and having company is plenty of reason she shouldn't be alone, to my way of thinking.

You're doing the right thing, mom.

The best answer probably is, "because it's illegal and I could get in trouble". If your state is like mine, kids have to be 13 to be left home alone. Of course, even at 13, it's not a really good idea on a regular basis. Unfortunately, teens without adequate supervision usually find a way to get into some sort of trouble sooner or later. And the homes where kids stay home unsupervised--at least in my neighborhood--seem to turn into the hangouts. I know a couple of mom's who would be very upset and disappointed if they knew exactly what was going on when their children were home alone. And I'm not talking about horrible kids. Even good ones at that age, don't have the sense to always do the right thing.

I've actually seen a lot of women giving up their jobs (or rearranging their hours) so they're home during the hours when their teens are home. In some ways, parental supervision is even more vital when they're beginning to flex their wings, and learning to make decisions. Especially considering that teens brains aren't fully mature. Until they reach their mid-20's, they don't usually have the ability to make logical, well-thought out decisions--that's a medical fact. Teens are working on pure emotion--and you know how much trouble that can get one into

You're definitely doing the right thing by seeing that she doesn't have too much time on her own, unsupervised. Even though she may complain now, you're the parent, and making sure she stays safe and healthy now will pay off in the longrun.

I don't what to tell you. Maybe there is a YMCA or boys and girls club that has programs for teens. It's an awkward age to deal with, childcare doesn't serve that age, but they aren't ready to have that much free time.

I didn't work for 14 years, then when I did it was as a substitute teacher. So when my kids are home, I am home. I'm sorry, I don't have options for you. But I do agree that your thoughts sound right on to me. It will be hard to take away a privilege later.

My oldest is almost 15, and I wouldn't even want to let him have the house to himself for several hours on a regular basis. I have no idea what I would do if I couldn't be here, especially since we have no family in the area. DS#2 will be 12 soon, I allow him to stay home by himself for no more than an hour when I run an errand near-by. I point out to them that they don't always make good choices when I'm standing right in front of them, forget about being home alone for very long!

I can understand exactly how you feel.

I think at that age, she could be left at home on her own, only for short periods. Not the whole day. If you do this you are saying to her "I trust you" and you are giving her the opportunity to show you that she can be responsible.

Saying "its a safety issue" and leaving it at that, is a good idea.

It is such a tricky age, because vacation care does not cater for this age, or doesn't where I live, and I have always wondered what parents do in these circumstances.

You sound like me, when you imagine bad things are going to happen if she is home on her own. But really, you know your child, she is probably going to be fine.

I can agree with your daughter when she says that you let her babysit and yet don't let her stay at home. Babysitting is a really responsible job, and she has proved herself there, to be a responsible young lady.

Perhaps you could reach a compromise with her...leave her for the morning at home on her own.

I can't imagine you would want to take away this privilege in the future.

You could remind her that with privilege, comes responsibility, and set some rules about staying home alone. Like no friends over, no using the oven, etc etc. No going out leaving the door unlocked.

Some ideas for you.

Actually, I know several families who do have 'babysitters' (supervisors?) for kids that age and even older if mom has to work (one family I know still had someone coming in when their oldest was a sophomore). Nothing wrong with taking the job of parenting seriously, in my book.

But a couple of suggestions. Does your town have a summer academy? Ours offers fun classes (cooking, theater, juggling, art, etc). A lot of kids that age, when they're too old to actually take the classes, 'graduate' to being teachers' helpers. It's a volunteer position, but it gives the kids something to do, they feel important, and they are starting to learn work ethic and getting a first entry on their resume.

Also, our town offers summer employment for kids--they might be a few years older, but something to keep in mind for the future. The kids are supervised, and put to work on various projects around town--caring for the lawns of the public buildings, cleaning the parks, etc. They're paid, and they can usually do that much younger than they'd be able to get a 'real' job.

What about summer camps? I'm not talking about sleepover or far away--but have you checked the local theater, dance studios, gyms, etc? They often have intersting summer activities for kids.