The other exception was that the sons of a helot could be enrolled as a syntrophos if a Spartiate formally adopted him and paid his way.

Others in the state were the Perioikoi, who were free inhabitants of Spartan territory but were non-citizens, and the helots

Descendants of non-Spartan citizens were not able to follow the agoge and Spartans who could not afford to pay the expenses of the Agoge could lose their citizenship.

Sparta could not readily replace citizens lost in battle

middle class, called the Perioeci

farmers and artisans who were the descendants of those peoples whom the Spartans had first conquered,

had no real political rights

the helots: a slave class descended from those peoples who had resisted subjugation by Sparta

Spartans attempted to control them by forming a secret society that annually murdered any helot suspected of encouraging subversion.

In Sparta, the goal of education was to create a strong warrior. 

Sparta's warriors were legendary

Spartan women, unlike women in the rest of Greek world, had a great deal of freedom.  Many ran businesses. Sparta women were free to move about and visit neighbors without permission from their husbands

In Sparta, boys were taken away from their parents at age 7. They lived a harsh and often brutal life in the soldiers barracks. Younger children were beaten by older children who started fights to help make the younger boys strong. Children were often were whipped in front of groups of other Spartans, including their parents, but they were not allowed to cry out in pain