The more complete version of this line of reasoning is (which I've seen more than once, but no links to hand, sorry) is:
After solidly internalizing the messaging of "teen pregnancy is the worst thing ever" & "sex leads to teen pregnancy", there's no "switch" to make those thought patterns disappear without a trace at the point at which it's "ok" (by whatever metric is relevant to the individual) to participate in sex, child-rearing, etc. So individuals find themselves dealing with long-term guilt at having sex and/or aversion to having children, neither of which is "rational" according to their values but which nonetheless is real and affects their behavior.
After solidly internalizing the messaging of "teen pregnancy is the worst thing ever" & "sex leads to teen pregnancy", there's no "switch" to make those thought patterns disappear without a trace at the point at which it's "ok" (by whatever metric is relevant to the individual) to participate in sex, child-rearing, etc. So individuals find themselves dealing with long-term guilt at having sex and/or aversion to having children, neither of which is "rational" according to their values but which nonetheless is real and affects their behavior.