If your mom and dad never married and split up before your born, you live with your mom and step-dad ever since and you are 16-years old, can you chose to live with your real dad if you are in contact with him? Or does both set of parents or one have to agree?

There are "stickies" at the top of this forum that deal with your question. However, the basic point in your situation is which parent has custody? I would certainly presume that's your mom since you say you've been living with her all along. The next question is, is there a custody order in place? In other words, does your mom have court-ordered custody or custody by default, with neither your mother nor father having gone to court to get a formal custody order? Do you have visitation with your father? If so, is it court-ordered or do your mother and father just agree on times and dates between themselves? These factors will play a role in how easy or difficult it will be for you to change your residence if you wish to do so. The bottom line is, you cannot of your own accord "choose" which parent you want to live with. You can certainly state a preference and in court the judge would give some weight to your stated preference but that, in and of itself, would not be the all-decisive factor. If there is a custody order currently in place giving your mother primary custody, then that would have to be changed by the court in order for you to legally be able to go and live with your father instead. On the other hand, if there is no court order and your mother is willing to let you go and live with your father on her own accord, then you can do that. If she's not willing, then your father would have to go to court and persuade the judge to give him primary custody in order for you to be able to make your move. As a final note, I have to ask, since your parents were never married and apparently never even lived together for any length of time, has paternity even been established? Meaning, has your father even been proven to really be the father, either by signing an affidavit of paternity or through a DNA test?

The short answer is that you cannot legally make this decision at 16. Your mother, of course, could CONSENT to a change in custody.

So many things

First was there ever a custody order thought he court,

Whose names are on the birth certificate

Was there child support ever paid, and was there a child support order.
** if not, mother can still go against him for support now,

Also if he has not found or been in your life for 16 years why do you want to live with him now, how about just starting to visit and get to know him

But your mom will have to give him legal guardianship or he will have to file for a change in custody to give him legal custody.

You as the child have no real choice, if he files in court you can testify