Answer:
by Randy Carey:
Since a minor does not have the capacity to contract, you can deny the loan application. There is no discrimination involved. The remaining applicant is free to reapply on their own.
Answer:
by Richard Insley:
Consistency is important. You have a joint application and one applicant is qualified. Handle this case the same way as if the other applicant is bankrupt, out of market, or otherwise unqualified.