If two children are the beneficiaries on a life insurance policy and one is under the age of 18 who gets the money for the minor child?

No one. Each child will be able to collect their share of the money when they are 18. The money for the minor child will be kept by the insurance company until the minor turns 18. This is why it is not a good idea to name minors as beneficiaries of life insurance policies if the money would be necessary for the upbringing of the child. Either name an adult that you trust or create a life insurance trust to be named as the beneficiary.