This is propaganda of the most obvious kind. You should have a retirement plan. Kids are not a plan.
There needs to be enough working aged people to run all the services a person relies on (utilities, health care, home maintenance, food production, etc). There also need to be enough people in the population to consume so all the investments in the retirement fund don't crash and burn.
At an individual level, a parent shouldn't be relying on their kids to pay for them in old age, at least not directly. But enough kids are needed to keep the world going and economies afloat.