Proto - I doubt UA would let you transfer 25K miles to a childs account (But I don't know the minutiae of thier rulebook). What they will let you do is claim an award which can be transferred to a third party.
Many programs have transferable award certificates - it's not the same as transferring miles, but the distinction is subtle. You generally can't, for instance, redeposit an award in a different account than it was claimed from.
Leroy is correct about BA - in fact, in the UK Airmiles program (and presumably Executive Club?), miles can be transferred to defined close relatives or to anyone who travels with you.
[This message has been edited by james (edited 04-24-2000).]