Well, kind of.
When Trishina died, one of the N/As was "unlocked" (I mean, the N/A on profile went away) and managed to have children with the new adult that was not "N/A". My theory is that they display an N/A on their profile because the game cannot have more than 2 adults at once (only the married couple, since they are not married they argue when trying to go for a baby). So the game treats them like children, except they can work (their earnings are not displayed on the "bank" page though), and have promotions (Yes, I got messages of the "N/A" having promotions).

I would say the problem is solved, the issue (I think) is the game not letting more than 2 adults in the same household (and I understand it, since making a game with polygamy would be very controversial), so when Trishina died, the "slot" for a second adult was unlocked and the older one of the two N/As took it (which happened to be the female, so I got a couple).