Apophis refers to Skaara and his symbiote Klorel as his "son".
I can think of two explanations:
- Apophis is a queen.
- Goa'uld are capable of sexual reproduction.
It would make a lot more sense for Goa'uld to have the option of reproducing sexually as they have genetic memories.
A queen can only pass on her memories to her offspring whereas in theory, sexual reproduction would combine the memories, and DNA of the offspring allowing for mixing memories (like a Harcissus except in the form a symbiote instead of a human).