Kids would detract from the story...She is very deliberately addressing adult issues ..
Kids are an affirmation of life and a symbol of the future.
She is making the point even if in deliberately that the falling system has no future.
On the matter of children in AS- Rand writes about children in ‘The Utopia of Greed’ wherein a mother speaks to Dagny about her reasons for taking the striker’s oath. It’s a very brief encounter, but a topic worth noting for future threads.
What I find missing is that Dagny is not considering the possibility that she herself could become pregnant and have children. Rand explains in detail everything the characters are thinking, considering, worrying about. But, in the 1950's, when the story is being written, the thought of pregnancy and children doesn't cross Dagny's mind.