Yes, you can, and the process is pretty much identical. You will still need to meet the requirements listed above and will need to be married to your multiplayer companion. Then eventually, a message will pop up on the screen for both players, asking them if they want to have a biological child or adopt a child. The only difference with this process is that players need to be in agreement, so if you player agrees but the other says no, then you won't be having a baby, sorry.