This response is for discussion purposes only. No attorney-client relationship is being created. If you need legal advice, you should consult an attorney in your jurisdiction.
It's unclear why you would want to put someone on a birth certificate if they are not the biological father. if you're in a situation where someone has expressed an interest in adopting, for example, that would make more sense. According to this clip from the PA website, it appears only the paternal could be "edited" into the certificate:
"How to Add the Father's Name to a Birth Record for a Child Born to an Unmarried Woman
As a result of Act 1997-58 that became effective January 1, 1998, a father cannot be listed on the birth record of a child born to an unmarried woman unless an Acknowledgment of Paternity has been filed with the Department of Public Welfare or there has been a court determination of paternity. If the parents wish to file an Acknowledgment of Paternity to list the father, it will be necessary to contact the Department of Public Welfare, Bureau of Child Support Enforcement at 800-932-0211, for forms and instructions. If both parents are unable to file an Acknowledgment of Paternity to list the father, a certified court order bearing the raised seal of the court and signature of the judge that establishes paternity, i.e. a Waiver of Trial, Support Order, or Custody Order should be obtained through their local Domestic Relations office."
Here is the link to the Pennsylvania department of health if you need more information. I'm sure they would answer your questions as well: