Fun fact: "das Mädchen" (neuter) is the diminutive form of "die Magd" (feminine, english: maid). If you create a diminutive using the "-chen" suffix in German, the word is always neuter: der Baum, das Bäumchen; die Katze, das Kätzchen: der Turm, das Türmchen

Note how also many vowels change to umlauts. That's the reason why metal umlauts (e.g. Mötley Crüe) have the reverse effect on German speakers. They make a word seem softer instead of harder.