And there's another thing to consider- these people live in a medieval-esqe time period, and in those days miscarriages and stillborn children were very common, and the infancy and childhood mortality rates were astronomical compared to today.
While this is accurate, don't forget that Thedas isn't presented as a true medieval setting. Not only are women significantly more empowered, but the general populace seems to be more educated than reality would suggest.
I am willing to bet money that this is the main reason why there are so few kids in the story. Kids don't play a big part, so kids aren't written in except in mentions. They aren't important.
...
Now, that STILL doesn't account for the fact that we've seen maybe a dozen children throughout all 3 games, but ultimately I'm going to say that BW just didn't feel like writing them in.
I've seen people say that it's weird to not see children in cities and other such remarks related to the presence of children. Personally, I don't mind in the least. If children are included, it would only be as some story device, and frankly, I'm not interested. I'm happy to run around as an adult, interacting with adults.
That's just me though, and I can understand why other people feel differently.
When he talks about his family, he alludes that his parents married for the sake of power and despised each other outright. This probably means that they only slept together for the sake of having an heir, and once they had Dorian they didn't bother going through the ordeal again.
Yeah... I really don't imagine that it was a pleasant experience for either of them.
Alexius though... he and his wife were actually in love, so that doesn't apply in his case.