Parent of a U.S. Citizens who is less than 21 years old is eligible to apply family based immigrant visas.

Please congress considers to modify this:
Family immigration IR5 visas: Parent of a U.S. Citizen who should be less than 21 years old

Reasons
This practice eliminates a U.S. Citizen child to receive better education in US and takes away the family union if the child's parent has to leave US due to visa issue, for example, L1 /L2/F1/F2 visa