Star Trek: 10 Things You Didn't Know About Data

Data was the fifth Soong-type android, the first three being B-4 and two other unnamed prototypes. These early androids were much less sophisticated and struggled to grasp even basic concepts. Lore came next, but his personality was dangerous and chaotic. He eventually summoned the Crystalline Entity to destroy the Soongs’ colony, then later went on to cause trouble for the crew of the Enterprise-D. When Data was made, the other colonists severely doubted that he would function as Dr Soong intended, but he turned out to be the most stable android yet, although completely devoid of emotions.

Noonien Soong also created an android of his wife at the time, Juliana, so Data's mother became an android too. She was even more lifelike than Data and lived her life believing fully that she was Human.

In the first season of Picard, we learned that Data also had a Human brother all this time: Noonien Soong's son, Altan Soong. Altan, along with Bruce Maddox, went on to create the Coppelius androids, more realistic synthetic lifeforms derived from just one of Data's positronic neurons salvaged from his brain. These new androids could be viewed as Data's children in a way. Some, like Fred from Discovery's fifth season, had the same pale skin and yellow eyes, but others had more Human appearances.

The A500 androids (like those who committed the Mars attack) were also based on the designs of Soong-type androids, but they were much less advanced, with highly limited communication skills and intelligence. Let's call them Data's cousins.