Some might think is a done deal on this issue. I am going to disagree strongly with several of you, whose viewpoint is NEVER hire boys to watch kids.
I strongly disagree, and don't think you should generalize by gender. You have had or heard of bad experiences and I understand that---let's not judge all boys that way.
I have 3 teen age boys. 2 would make excellent sitters....not of babies, but of kids 6, 7, 8, etc.... And just from a comfort level. My boys would prefer to be able to communicate with the ones they were in charge of. My third son, is very shy and would not babysit, even if asked. We have raised our boys to have the utmost respect for others and the rules of society and I would be offended if people generalized them as possible molesters.
When my boys were young, we had both boy and girl babysitters at various times. The boys did far better jobs than most of the girls. The boys played baseball with them, or basketball, or something and made it fun! The boy sitters obeyed our house rules much better than the girls! They limited TV, never talked on the phone and never invited their friends over to our home!
We had one girl one time, who defied our orders to limit TV viewing and let the kids watch TV all night so she could talk to her boyfriend on the phone. When my oldest was 9, we had a girl sitter who peeked in on him in the shower stall, without knocking or anything. One year later, we had a girl's boyfriend show up on a Saturday night looking for her. She had been here Friday evening sitting. They boyfriend was confused on the days and was stopping by OUR home b/c the sitter had invited him!
Needless to say, these girls were only here once and we never, ever referred them to others. From that moment on, we decided we needed to know the families well and get references, and talk to our kids a lot before and after the sitter, whether they were boy or girl.
Someone asked why would a boy want to babysit? I can think of many reasons and non of them imply they are a molester. Many boys really like kids the same way girls do. Some boys are the youngest children and like having younger ones to watch and play with, b/c they don't have that opportunity otherwise.
Some boys have a huge load of stress placed on them at home or school and are very responsible. They like to watch kids b/c they can be trustworthy, and have fun and finally get an opportunity to play.
In summary, H., I like your idea of hiring 2---a boy and a girl. Sounds like you've done a lot of thinking about it and know the family well. I think you are doing the right thing.