A nice writeup over at GamePro can be read about 10 ways the Sims series has evolved throughout the year.  Here’s an example of one below:

The Sims 2 introduced a proper aging system to the game where Sims could start life as an infant, and then grow to a toddler, a child, a teenager, an adult and then eventually reach old age. The Sims 2 University expansion and later The Sims 3 both added young adult phases of life, too. Before that, the closest the first Sims game ever got to aging was the Making Magic expansion that contained a spell to turn a child Sim (or a Sim pet) into an adult human. I consider this a less-than-perfect way to handle aging. One time when I magically grew up a child Sim into an adult, she immediately began making out with her mother. Ew.

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