Argosian woman, wife of Alekos and mother to baby Dan-el. Alekos took Thetys to the temple of the god Pelops to pray for an ease of birth pains. This was when SG-1 arrived, and Dr. Daniel Jackson ended up delivering her baby boy. She was some twenty days old at the time.
When Jack O'Neill infected with the same nanite technology used by the Goa'uld to accelerate the population's rate of growth, he had to remain behind on Argos for a time. There he grew old in a matter of days, eventually leading an uprising against Pelops. Along with her husband and others, Thetys declared that if Pelops thinks of them as slaves then she no longer wished to serve him.
With the nanite experiment destroyed, Thetys and her family were free to live out the rest of their lives at a normal pace.
Brief Candle - With Dr. Jackson's assistance Thetys gives birth to Dan-el, and stays in the vicinity of SG-1 during their stay on Argos.