Nice job fucking up and posting the wrong link the first time, then.
So let's unpack that.
Their citation for that claim is
a study (
archive) which estimated that 37.4% of all children will experience a CPS investigation at some point before the age of 18 (and they estimate that 11.8% of children will experience a
substantiated investigation, meaning that roughly 32% of the investigations are substantiated). First of all, that's an
estimate, so they can't just cite it as though it's a fact.
Secondly, but more importantly, they appear to have somehow just mashed numbers together according to a secret magic formula (they don't say how; they just cite
the census) to determine that 37.4% of children corresponds to "49 million parents." I don't know if they used average household size or number of adults with children under the age of 18 living under their roof or what; they just cited the fucking census so they could've done literally anything.
So we've got some bad (or questionable at best) math that was done by a biased public interest group which is clearly being alarmist and trying to spread fear among parents that the CPS will come take their kids away... the "FAMILY PRESERVATION FOUNDATION," a
not-for-profit organization "dedicated to the idea of rescuing children from unwanted forced parental separation" (
archive), which also goes under the name "
Stop CPS From Legally Kidnapping Children" (
archive). That's
your source.
And finally, as
@lamp pointed out, 49 million parents would not even be "most;" it would be less than half.
I was really going to rail at you harder for fucking up, but frankly your mistake was reading the "FAMILY PRESERVATION FOUNDATION" and being gullible, because
they failed to adequately explain their source or their reasoning and all you did was grab the closest citation that
they provided (maybe because you thought that it would be more a credible source to cite than an article from the "FAMILY PRESERVATION FOUNDATION").