Would I be considered a putative father?

First off, kudos to you for researching this. The law governing unwed fathers is very complex and not at all what people think it is...but most people enter into this situation blindly.

Technically the term "Putative Father" means anyone who MIGHT be the child's biological father. The term is only relevant when it comes to unwed fathers.

The Putative Father Registry exists to make adoption easier. The courts said that a mother couldn't put her child up for adoption without giving the bio-dad a chance to object in court. This created problems in situations where Moms weren't sure who the father was. States experimented to see how much they could reduce the bio-Dad's rights without the courts objecting. The states created a system whereby it was possible for an unwed father to object to the adoption of his child, but deliberately made it so obscure and confusing that few fathers would figure out what they were supposed to do. Thus the Putative Father Registry was born. Any unwed father who hasn't filed with the putative father's registry is deemed to have waived his right to object to the termination of his parental rights. It's really only relevant in the adoption context.

If you DON'T register with the Putative Father Registry before the child is born and file a paternity suit after the child is born, then technically your girlfriend could put the child up for adoption without your consent. (Or if you breakup and she remarries she could have her new husband adopt the child.)

So, yes. You should register with the Putative Father Registry.

If you get your name on the birth certificate and sign the Voluntary Acknowledgment of Paternity then you will have all the responsibilities of the child's legal father. Whether it gives you all the rights of a father is a different question. It doesn't do so in all states, and I'm not sure about Ohio. The Voluntary Acknowledgment of Paternity was really created to facilitate child support enforcement and keep people from filing so many paternity suits.

Of course, most of these issues are kind of irrelevant as long as you stay together and she is cooperative.

Personally, I think any unwed father should hire a lawyer. You should sign a contract to determine what happens to the house if you break up. Do you want her to be able to visit you in the Hospital? Sign a health care proxy. Do you want to be able to take her kids to the pediatrician? Have her grant you health care proxies for the children.

If you and your gf both acknowledge paternity, most states just accept it as fact unless disputed.

As for stepparents rights, some states acknowledge a stepparents role in the child's life to the point that if you were to divorce the parent you could gain visitation. But rights are difficult and hard to find.

In almost every case, you will not have rights to the child until you either marry the mother or establish them in court. There needs to be some kind of legal proceeding to seal the deal.