“But what does he call you?” is easily the number 1 question both my spouse and I get when it comes to our son. Apparently this is the most pressing issue when heterosexuals see gay parents. The short answer is I’m “Daddy” and he’s “O’Daddy.” The long answer is, we never specified to our son what to call us, and we both called ourselves Daddy in the beginning. As the stay-at-home parent, I was around more and referred to my spouse as “Other Daddy,” which he picked up and it evolved into O’Daddy. It’s completely adorable, and it stuck.
There are several options you can choose from when you are same-sex parents. Among my gay dad friends, I’ve heard Papa, Papi, Abba, Pops, and Father, but I’m sure there are more, and I’m sure some of them are awful. There technically isn’t a right or a wrong in this situation, but it should be something the family is comfortable with. Also, there should be some distinction. If you recall, in the movie The Kids Are All Right, both of the parents are called Mom, which is confusing as fuck. Then we have Modern Family where Lily calls Cameron "Daddy" and Mitchell "Dad," which works fine until she is older — then do they both become "Dad," or will she be calling Cameron "Daddy" when she’s 50? "Hi, Daddy, I'm feeling menopausal." Clearly the semantics are important.
My suggestion is to do whatever feels right for you and your family. For us, we let it happen organically, and as a result everybody is happy. Others like to have all the details figured out ahead of time, so by all means, plan away. As long as your kid isn’t calling you “Top Daddy” and “Bottom Daddy,” it should really be the least of your worries, though it will always be mysterious to straight people.