Joint responsibility, as its name suggests, means sharing the responsibility.
Even today, in most cases, one partner takes on the primary burden of childcare and household tasks (usually the woman), while the other helps out in some areas (usually the man).
However, this means that one person bears the full weight of responsibility, coordinating, ensuring the necessary resources are available, and solving any issues that arise, while the other simply helps, playing a secondary role.
If we raise children and live together in a jointly responsible way, both of us are equally responsible for the tasks and must carry them out completely. No one has a secondary role; we are not just helping. We are "owners" of that task and must ensure it is done properly.
For example, if it’s our turn to prepare dinner, it’s our responsibility to think of the menu, make sure we have all the ingredients, prepare the meal, and serve it.
If instead, to make dinner, our partner has to tell us what to cook and buy the ingredients, then we are not being jointly responsible.
Similarly, if it’s our turn to do the grocery shopping, we need to check what we need, make the list, go to the supermarket, and then put the items away at home.
If, to do the shopping, our partner has to give us a prepared list and then tell us where to store each item, then there is no joint responsibility.
And lastly, if we are going to bathe the baby, we need to know what temperature to set the water, which shampoo or soap to use, how to bathe them, which towel to use, then put on the diaper and pajamas, and finally put everything back in its place.
The opposite case would be if, to bathe the baby, our partner had to fill the tub, prepare the towel, diaper, and pajamas, and then put everything away afterward.
As you can see, it’s simpler than it seems, but it involves starting to see things differently and understanding household and childcare responsibilities as a joint effort. That is, there should not be a responsible person and a "helper," but an equally committed couple that divides tasks according to each person’s availability, knowing that both are equally responsible and valuable in parenting and the household's functioning.