How Can We Bring Our Son into United States?
 
Question:

Both my wife and I are U.S. Permanent Resident. My baby son was recently born in my home country, not in U.S. Now, my wife wants to bring my son to U.S. Could you please let me know how can we bring our son into United States? and does he need a visa to get into U.S.?

Answer:

A baby becomes a U.S. citizen automatically if he or she was born in the U.S. A child born abroad of permanent resident parents may enter the U.S. without a visa, provided the child is accompanied by a parent upon that parent’s initial return to the U.S. within two years of the child’s birth, with documentation showing the parent-child relationship.

If the permanent resident parents leave the child abroad with family members and return to the U.S. without the child, the child must have an immigrant visa to enter U.S.

http://www.greencardfamily.com/question/question2015/Child-Visa_030215.htm
http://www.greencardfamily.com/residentspouse.htm