The mortgage payment will actually force them to live even more responsibly, and that'll be a good lesson and character builder we think.And what if it doesn't work like that and they can't make the mortgage payments? Will you bail them out or will you let them go into foreclosure?And why do you think this is the best way to teach them a good lesson and build character? What business is it of yours how they learn their lessons and what lessons they learn?From what you've written, it almost sounds like you think saddling them with a big mortgage will force them to grow up and live however you want them to be living. But it's not your choice how they live.I don't see it as being a good thing that you think they will have to live more responsibly and a more austere existence to support this large mortgage, particularly as you've said they are already living responsibly and seem to have no debt.Personally, it seems to me like you and your parents may be butting in where you don't belong, and it almost seems as if it's to control how they live their life.I'd recommend staying out of it and letting them do it like the rest of us. They can earn their money, save the downpayment, and find the house that meets their needs, all on their own and on their own timetable. There's nothing wrong with starting slow, and if it seems like they are happy, which it does, why do you think things need to change?