You should really think about this for a minute: him being the father isn't the same as them having such knowledge. Him not denying it now isn't the same as him telling them :it is my child, at the time of the incidentHe's not denying it. Besides, if he's the father, it proves that he had sex with her. Unless it's some sort of miracle.
The headlines grabbing attorney stated her case depends first upon proving the religous school is not a religious organization.
My wife, before marriage, was suspended/expelled from her Christian college when she acknowledged she was spending weekends at my flat, though it was not a sexual relationship. While many appeared on her behalf and the university allowed her to continue courses off campus hoping not to lose her permanently and that she'd come back to the fold - which she would not (and that concerned me as we had no committed relationship at all and I didn't want her to lose her career goals), at no time was a lawsuit considered because there would be no basis. The rules about being in the dorm at night was not subject to exceptions except for married students.
"I HATE THAT RELIGION'S TENANTS!" is not the basis for a lawsuit by seeking a jury to agree with the hatred or having them judge the religion's beliefs.