I'm not an anti-natalist nor am I planning to have children, but I am generally interested if there is a good reason to have children.
It is obvious that capitalism makes it hard to raise kids but even without capitalism, is there a good reason to bring new humans to earth?
I don't know am I caring too much?
Raising children is certainly not easy and comes with its own set of issues, but hopefully most would agree that education is very important to the socialist cause. Children are at the age where they have time to learn, because humanity has decided that child labour is not acceptable, and they are more receptive to all sorts of information whether progressive or reactionary.
Educating children and radicalizing strangers are not mutually exclusive activities because of the division of labour. Some comrades will be teachers, some will be communicators (propagandists), others might be workers, farmers, soldiers, students, scientists, leaders, or even capitalists (yes!), and certainly all of them can have children while taking on those roles. Maybe this is a foreign concept to some, but children don't have to be raised solely by their own parents, because grandparents, comrades, friends, or relatives can all help out.
I am aware that the nuclear family is a bad model for raising children. My brother lives with our parents and is raising a child. Even with their help, he still barely has time to do anything between raising his kid and his job. If he were a communist, his participation in an organization would take a significant hit. Raising a kid is a whole-ass 18 year commitment even with help, especially in the first few years.
You could radicalize so many more people with that time than just one child, and as another user pointed out, your child could always turn out like Pete Buttigieg or Kamala Harris: neoliberals with Marxist parents.
Raising a kid is an "18 year commitment" only if you view children as a product in a capitalist society that takes 18 years to produce. Children are a lifetime commitment, as is any serious relationship whether bonded by blood or not.
So what happens if your kid turns 18 and becomes reactionary one way or another, is this person then different from the strangers who you want to radicalize? Where do these strangers who you want to radicalize come from in the first place, were they not children once? Do you then prioritize radicalizing strangers who do not have kids over those who do?
Even if the traditional (bourgeois) family relation were to be abolished (as touched upon in the Communist Manifesto), the relationship between people will still be there just by their existence in society. As Marx also mentioned in "Theses On Feuerbach" (https://www.marxists.org/archive/marx/works/1845/theses/): "But the essence of man is no abstraction inherent in each single individual. In reality, it is the ensemble of the social relations."
I also want to mention that other than the traditional idea of reproduction, there may be more options in future that have ethical issues like surrogacy and artificial wombs. These potential options do not change the physical blood relations between mother and child, but if they were to become mainstream along with accompanying societal measures for childcare, they would fundamentally dismantle the traditional family unit too.
All this is a long-winded way of saying, how children will be raised in future might be different from today, but it doesn't change the fact that you need children for society to continue functioning. Children are the future, not just philosophically but also materially because the old will pass and the young will carry on the flame.
Throughout my comments I have not mentioned the emotional value of having children, because I think it's easier to explain the practical value of children to society to someone who doesn't understand the basic idea of why reproduction is necessary to humanity.
Final point that I haven't mention, is that revolution involves bloodshed, and fighting counterrevolutions too.
Like I said, if you don't want to have kids, that's fine, some great communists like Zhou Enlai and his wife Deng Yingchao don't have kids either. You can use any reason to justify it, no one is forcing you to have kids. However, the consequence of not having kids is very clear, there will be less potential comrades on your side.
Also, if you cannot bring up your own kids to be socialists, how confident are you in radicalizing strangers?