How could this possibly be true? That's a generational wipeout--or a complete transition to bastardry as the preferred mode of propagation.
As a Gen Xer, I can tell you that there are other big reasons, too.
Many kids my age were latchkeys that were left to fend for themselves, and whose parents were either long-divorced, or MINO (married in name only). A lot of us lived in such screwed-up homes, that it was hard to justify the idea of putting another generation of children through that.
On top of that, there is also the factor of a ruined economy, and no more job (let alone ‘career’) security. Hence, for a lot of the young men especially, of my generational cohort, marrigeable women don’t exactly see us as a good prospect.