...or upon notice of fatherhood? my son is 11 and i notified his father when he was 2 yrs old that he is his father. That time and 2 more times after he claimed he could not afford a paternity test that he wanted. Now 9 yrs later, the test has been taken and he is the father. Does he owe child support for 11 yrs? 9 yrs or only from after the test confirmed he is the father?