True Equality Act or sometimes referred as the Last Equality Act (because it was the last gender related legislation) was the first solar system wide legislation that was passed in year 3022. This legislation was mentioned only once in Two Clusters which is [Cecil arc]  [Cecilia] .
At the time of the legislation, mankind had spread to Venus and Mars, and the legislation was the first one to take an immediate effect on all three planets simultaneously.
The legislation removed lastname with exception being clans. The reason it was called True Equality Act was the unfairness when it came to children inheriting father’s lastname in general. After the legislation came in effect, everyone became lastname-less. Thus, removal of the last unfairness for females, at least on paper.
Clans were exempt to this. However, children no longer inherited father’s lastname by default. If a child’s mother was more politically powerful, the child inherited mother’s lastname if the couple were from two different clans.
Another lore file “Clan structure” explains further on this.
This legislation was challenged a few times shortly after its approval. However, True Equality Act stayed on and was accepted as norm as generations passed.