It's trying to make a point about the urgency of the climate crisis. Her logic is that the more they delay making children the more the children will suffer from the climate crisis in their lifetime and if they make them soon they might die without facing too much of it. I guess the guy and the stuff around him is meant to give a hippie/liberal/sciency feeling (clothes, facial hair, bike, calculator, telescope).
The comic is a mess even after figuring out the weird logic and message.