I live in USA and I lived with a woman for 5 years without being married to her (she is not Muslim). During this time she got pregnant and we got a baby boy (she is his mother of course, and I'm his father). The day she delivered the boy she gave him her family name without asking me. I learned that later on, so he does not carry my name now. I tried to change his last name, to take mine, but she refused to change his name. Is this boy considered as a bastard or not? We are not living together any more.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

There is no doubt that being on intimate terms with such a woman, without legal marriage, constitutes a form of dissoluteness, vice, and a major sin.

It is your duty to repent, regret, and seek Allah's forgiveness. So, you have to hasten in repentance before it is too late.

For more benefit on marrying a girl with whom one committed Zina, please refer to Fatwa 81160.

As for your illegitimate child, there is no relation between you and him since he is born out of Zina (fornication or adultery). He is to be traced to his mother and both of them can inherit one another.

For more benefit that the child is traced back to the fornicator (or adulterer) if he requests that the child be traced to him, please refer to Fataawa 97254, 83680, 168603 and 84788.

For more benefit on the marriage of a fornicator (adulterer) with the woman he committed Zina before repentance, please refer to Fataawa 329617, 188393, 158403, 135767, 95615, 405622, 148021, 378067 and 86903.

Allah knows best.