Season 2, Episode 9 was where Maddox tried to argue Data was the property of Starfleet and was defended as being a sentient being.
Season 3, Episode 16 was were Data created Lal. He made the point that as a "living" thing he had the desire, right and duty to procreate. But his experiment failed.
Season 4, Episode 11 shows Data in contact with Maddox, assisting him with his work on androids.
During season 6 is where Data painted the "daughter" painting referenced in Picard.
Sometime after that - perhaps quite a while after that - Maddox creates an android, basing her appearance on Data's painting.
This is a continuation of a thread about Data's desire to be a living being and it weaves in with TNG storylines fantastically.
Type louder, please.