I am always a bit anxious about the racialist implications or under-currents of films like this, which is presumably why academics do not take up the issue. It can be presented easily in terms of white Christian Europeans/Americans are not reproducing, whereas other races are.
The response of most governments is to allow economic migration, which gives us a pool of educated trained taxpayers, who support the economic needs of an increasingly ageing and long lived population. Of course what we tend to do is take the best from those nations that are reproducing, healthcare workers from Africa and Asia, are an obvious example.
The other side of the coin is that we discourage the growth of the "native" population. In this parish I think the largest family living in the parish has three children. Here it is in part because of the housing stock, so many small flats in old town houses with steep stairs and no gardens means larger families move out, cities everywhere are not child friendly.
But there is something more fundamental, some term it the "contraceptive society" or "contraceptive mentality". There is a prejudice against couples who have more than the two point whatever children.
Legislation is increasingly anti-family and anti-child, so much so that it sees children as not being integral to the family, or the family as being primarily about producing and bringing up children.
The Catholic understanding of children as a blessing, a gift that should be welcomed, is easily turned on its head by economic pressures, so children become a burden, a financial handicap. Green politics, an increasingly strident voice among the young, see children as a pollutant, as a source of destruction for the planet.