Traditional marriage has experienced a shift in popular culture from “cornerstone” to “capstone” of adult achievement. As a result, many young men and women are delaying marriage; indeed, today’s generation is marrying later than ever before.

For poor women, or those with low levels of education, late marriage has resulted in demographically unprecedented nonmarital birthrates. But for young female professionals, children during early life are often out of the question. And, unlike their counterparts of lower socioeconomic status, they have the means to both willfully prevent conception and push back the hands of the proverbial biological clock.

The odd thing is that early childbearing outside of marriage is culturally and economically incentivized for those of the lower class, whereas the same mechanisms operate to discourage childbearing at all for women of wealth and high social standing.

Among the poor, childbearing is still seen as a rite of adulthood, a chance to achieve some form of success and personal fulfillment. Olga Khazan quotes a Johns Hopkins sociologist, Andrew Cherlin, in an Atlantic article:

‘Many young women think they will be able to care for the kid—they have a mother who can help, a sister they can rely on,’ Cherlin said. Particularly among the very poorest Americans, ‘this is a way a woman or man can be a successful adult when all other paths are blocked.’

For the wealthy, however, children born outside of wedlock present a significant social and financial burden. Educational and career successes are the milestones used to judge success as an adult—meaning that young female professionals often choose to delay marriage and children.

Because marriage is no longer a moral prerequisite for reproduction, economics and personal preference are left to determine whether or not marriage occurs. As a result, those stricken by financial hardship have all but abandoned marriage. It demands resources they simply do not have: money, time, and long-term commitment.

Affluent women, however, have been proven to reap disproportionate financial benefits from delaying marriage and child rearing. Eleanor Barkhorn, in an article for the Atlantic, says that women “who marry later make more money per year than women who marry young.” There is a 56 percent increase in income for college-educated women who marry after 30, relative to the same group who married before age 20.

Thus, we have a boom of single mothers among the lower classes and a scarcity of mothers altogether among our professional and upper classes. The poor are unable to manipulate biology as effectively and end up having children at roughly the same point in their life as they always have, albeit outside the stability of a marriage. But the affluent can afford to cling to the normative marriage-then-children pattern, using money and technology to delay childbearing until they have found a suitable spouse.

The pattern is cruelly self-reinforcing. Young women raised in the broken homes so common among low-income social circles often grow up to perpetuate the same destructive cycle. Young women raised among the elite, on the other hand, feel overwhelming pressure to postpone childbearing for the sake of professional success.

In both instances, marriage has been relegated to secondary status. There is no longer any moral force behind the institution and, as a result, it is discarded or delayed for the sake of financial interests. Families are not a commodity; a household is more than a mere microcosm of our capitalistic society. But until something changes, the rift between the childless elite and spouseless poor will only continue to grow.