With how many people there are out there, even something that happens to 0.1% of people over their lifetime will happen to 200k people living in the US right now (assuming 200m pop, which I think is low now). Assuming an average life expectancy of 75, that averages 2666.6 per year, or 7.28 per day (assuming every year is a leap year).

I don't know what the odds are of having kids at 20, but I'd guess the conditional probability of two successive generations both having kids at 20 is way higher than 0.1%, which means there's more than 7 new ones each day. And any of them might post this kind of thing where they talk about something their grandparent bought new.