Your best option imo would be to make sure your kid(s)' account(s) remain(s) active (don't let it/them expire) and keep them flying until they hit 25K, then use the kid(s) account to redeem an award for your benefit. If you have two kids, you could also have each kid redeem a one-way domestic award for you to travel on (or the mileage portion of an upgrade). If a lot of traveling is in your family's future, then I'd keep the account(s) growing until a more valuable award can be redeemed....

I also have a young child and my wife and I are allowing her mileage balance to accumulate until it becomes of greater value, at which point we'll redeem it. All that organic milk and all those stuffed animals-- the least she could do is get us all to europe in J, right?

Too bad one can't pay for preschool with FF miles....