Question: I am 22 years old, and a US Citizen. My father came to the United States with a tourist residency about 10 years ago. He is now 47 years old and lives in the US still. He has paid his taxes except for these last two years. Can he apply for the US residency? Is it true that he needs to serve a 10 year ban?
 
Answer:  Yes you can.  US citizens 21 years or older may petition for their parents.  Since he entered the US legally, he can adjust his staus in the US(therefore no 10 year ban).  Just file I-130 and I-485 with the USCIS.  Make sure he does not leave the US until he receives green card from the USCIS.