I think it was just those traits you can no longer casually try for a baby
I'm not sure that the traits a sim has make much of a difference whether a sim gets pregnant or not with Try for Baby. Try for Baby does not always cause a pregnancy every time. The default pregnancy chance setting is 80% so you just might have been unlucky with the two sims involved and it just might take trying several times or more. But I do know that sims with those traits can get pregnant or cause a pregnancy as I have sims with those traits that have had kids in my main save.
The negative hit on romance does come from the traits and I think it's from the Hates Children trait. Non Committal sims just usually give you trouble when asking to marry as they will turn down proposals a lot.
Hope this helps.
