So much this. If a team is run so "lean" that an extended absence for anyone can create a crisis, that seems evidence that the team is run excessively "lean".

So much this. If a team is run so "lean" that an extended absence for anyone can create a crisis, that seems evidence that the team is run excessively "lean". And this is not just for parental leave: What if one of the singles has a hang gliding accident necessitating a lengthy recovery? What if somebody quits? If that invariably leads to overwork for the remaining team members, you risk a cascade of departures/burnout, and even if you get lucky and run for a few years with minimal slack and no major absences, it's likely that this has consequences for the well being of some of the team members.