3.2.  Marriage and the Paternity Presumption

Under the common law, there was a presumption that a child born to a marriage was a child of the husband.  This presumption could only be overcome by a showing of sterility, impotency, or that the husband had no access to his wife at the time of conception. 

In recent years, many states have adopted more relaxed rules, permitting the presumption to be rebutted under other circumstances.  In California, the presumption can be challenged by a presumptive father or child for any reason as long as it is raised within two years of the child’s birth.  In the same period, the mother can challenge it only if the biological father has filled a written declaration acknowledging paternity.  In either case, blood testing is used to resolve the paternity dispute.  Once the two year period has elapsed, however, the presumption is conclusive, unless the common law grounds can be established.

The Uniform Parentage Act (“UPA”) (2000) has an even looser standard.  A proceeding to challenge the paternity presumption can be maintained within two years of the birth of the child by the presumed father, mother, or any other individual.  Thus, in contrast to the common law or California rule, the presumption can be rebutted by any party as long as it is asserted in the two-year period.  After this time, a proceeding can be maintained at any time if two conditions are satisfied: (1) the presumed father and the mother of the child neither cohabited nor engaged in sexual intercourse with each other during the probable time of conception; and (2) the presumed father never openly treated the child as his own.  With the UPA, the common law approach is essentially eliminated.

What effect do the different rules have on the male’s procreative output?  Consider a conflict between a faithful, married man (“faithful”) and a male intruder (“intruder”), who is married himself, but maintains an extra-marital relationship with the married man’s wife. 

Under the common law rule, as long as the married man was cohabitating with his wife, and not impotent or sterile, any child born during the marriage was conclusively presumed to be his own.  As a result, a child who was a product of an extra-marital  relationship was considered the husband’s progeny, despite the lack of his genetic contribution.  The cuckolded husband was stuck supporting the intruder’s baby, and the intruder walked away unscathed.  Assuming that faithful stayed married, and that the intruder continued his relationship with both his legal wife and his paramour, the married man’s reproductive output was reduced, while the intruder’s was increased over what he could produce with one wife, alone.  For example, if the intruder fathers a child from his paramour every other year, while continuing to produce one a year from his own wife, he will have six children at the end of four years.  Faithful will end up with only two biological children since the intruder seized the two other yearly opportunities.  In this example, the intruder produces three times the number of biological children that faithful does, without having to pay the price.

The common law rule encourages adultery because it makes it difficult to challenge paternity.  This is good news for the adulterous couple because it allows the intruder to maximize his reproductive output, and the wife to make her choice of who is going to genetically father her offspring, without loosing the economic assistance of old faithful.  Even if faithful discovers the deceit, the common law rule restrains him from getting released from the child support obligation because he is presumptively the father, and fathers have the duty to support their children.  The intruder makes a child with his paramour, and faithful pays the bill for it.

Why should the cuckolded husband put up with it?  Assuming that adultery is uncommon, faithful might be better off tolerating the occasional fling, rather than destabilizing his family unit and harming his biological children emotionally and socially by the turmoil of a paternity suit.  In circumstances where cheating is infrequent, faithful might let the rare intruder get off, even if it means the added burden of supporting intruder’s baby.  Moreover, if adultery were so uncommon, and preserving marriage was a high concern, in most cases where a husband was in doubt about his paternity, he would be dead wrong, and letting the paternity challenge proceed would undermine and devalue marriage.

The California rule eliminates the intruder’s advantage, permitting the husband to challenge and rebut paternity as long as he does it early enough after the child’s birth.  The UPA rule goes one step further, giving the intruder, himself, the right to challenge the paternity presumption.  This modification takes away the woman’s right to chose a father/husband.  In the common law, she was free to marry one man, and use another to create a child.  The intruder father had no authority to challenge it, and as long as faithful remained quiet (or unaware), the decision was final.  The UPA rule strips the female of this power, leveling the playing field.

Under both rules, if faithful can prove he is not the genetic father, he can escape the support provision and not be economically harmed by his wife’s deceit.  With the paternity presumption rebutted, it becomes the mother’s burden to identify the intruder as the biological father, and institute appropriate proceedings to obtain support.   The intruder is now at risk from an economic standpoint.  He must be more careful if he intends to avoid paying for his extra children, and maintaining the extra-marital relationship with no financial or social strings attached.

In this analysis, adultery is encouraged under the common law, but discouraged by the California and UPA rules.  Why the difference?  One reason may be a change in moral code.  When the common law was adopted, sexual activity outside the marital unit was deterred by societal pressure produced from the group’s rigid moral code.  If the point was to prevent one male from stealing procreative opportunity from another, this could be accomplished by strict monogamy rules, and paternity presumption did not have to serve this purpose.  As morals loosened, and the threat of intruders in the nest became more serious, another approach to policing it became necessary.  Relaxing the paternity presumption by allowing faithful fathers to challenge intruders in the nest, made it more risky and costly for adulterers to cheat, replacing the group’s moral code as an adultery deterrent.