Drawing evidence from what we have narrated in the established hadith from Sayyidah Aishah and Sayyiduna Abu Hurayrah (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "The child belongs to the (owner of the) bed, and for the fornicator is the stone (deprivation)."
So he (peace and blessings be upon him) did not give the fornicator's fluid (semen) any sanctity.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / Q13889