## Facts

- K.E.M. (mother) was married to H.M.M. (husband) and had an extramarital relationship with P.C.S.
- The child, G.L.M., was conceived during the affair and born on July 30, 2006, while mother and husband were still married.
- During pregnancy, mother told husband he might not be the biological father and that P.C.S. could be.
- DNA testing shortly after birth excluded husband as the biological father; husband was present at birth but refused to sign the birth certificate.
- Despite knowing he was not the biological father, husband lived with mother and for nearly four years acted as the child’s father, including providing emotional and financial support; the child used husband’s surname and called him “daddy.”
- Mother and P.C.S. continued their relationship for years; the child sometimes accompanied them.
- P.C.S. ended the relationship in May 2010; mother then filed a child-support action against him while still living with husband.
- Mother and husband separated in June 2010 but remained married; they continued filing joint tax returns and claimed the child as a dependent.
- P.C.S. moved to dismiss the support action, invoking the marital presumption of paternity and, alternatively, paternity by estoppel based on husband’s parental role.

## Issues

1. Whether paternity by estoppel remains a valid common-law doctrine in Pennsylvania.
2. If so, whether and how courts must assess the child’s best interests before applying estoppel to bar a support claim against an alleged biological father.

## Decision

- The Supreme Court of Pennsylvania held that paternity by estoppel remains viable in Pennsylvania.
- The Court held that estoppel applies only if a developed evidentiary record shows applying it is in the child’s best interests.
- The Court reversed the order affirming dismissal of the support action and remanded for further proceedings because the record was insufficient to determine the child’s best interests.

## Legal Principles

- Paternity by estoppel is an equitable doctrine that may treat a non-biological father as the legal father when his conduct and the child’s reliance justify that status, but it is not automatic.
- The welfare and best interests of the child are the controlling considerations for applying paternity-based legal fictions, including estoppel.
- A court may apply paternity by estoppel only after fact-finding adequate to evaluate the child’s relationships and the likely emotional and financial effects of recognizing or rejecting the alleged biological father for support purposes.

## Conclusion

Pennsylvania continues to recognize paternity by estoppel, but courts may bar a support action against an alleged biological father on estoppel grounds only when, on a sufficiently developed record, doing so serves the child’s best interests; because that showing was not made, the case was remanded for further proceedings.


K.E.M. v. P.C.S., 38 A.3d 798 (Pa. 2012)