Government control over reproductive rights is terrifying. But I wonder if population control will be an issue at all? Referring to sweeping generalisations here, but educated people have fewer children, religious people have more. In a society that is focused on science and knowledge, where religion is is a personal practice rather than a part of the societal fabric, there will be fewer people having children anyway. Oh, and having free contraceptives to reduce unplanned surprises is a good idea too.
I had a quick google of "reasons why people have children" and I got the following list, which is quite interesting (particularly as someone who never wanted children). Rather than "controlling" the population, if you look at why people have children and support alternatives lifestyle choices then you reduce the number of people having kids for reasons other than wanting to be a parent - which is really the only reason anyone should have kids!
- To have someone to take care of them when they get old.
- To carry on family name.
- Because they love babies.
- It's human nature.
- Pregnancy and childbirth are life experiences.
- To let their children (who don't exist yet) experience the joy of existence.
- To give your parents grandchildren.
- To embody love for each other.
- They want children of their own, with their own bloodline.
- They don't know. (it's just what everybody does)
Ideally, IMHO, people should only have children because they want the responsbility and reward of being a parent. Most of the reasons in the list above are cultural; ideas that are programmed into us so we continue a tradition. By the time Asgardia has a space civilization, the culture will be different. Our value as individuals will be based on what we do with our own lives, regardless of whether we create new ones or whose name we inherited. We can have a respected aged care system so we don't fear a future without our own children as carers. We can encourage other pursuits and experiences that provide joy and give value to the world. We can find fun new meaningful ways to express our love and devotion to each other.
If the only people having children are the people who deeply desire to be parents, the population will probably be sustainable.
And definitely have free contraception. It's fantastic.