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The Humanoids
Human - 1/2 chance of getting male, 1/2 chance of getting female
Harpy - 1/6 chance of getting male, 5/6 chance of getting female
Mermaid - 1/2 chance of getting male, 1/2 chance of getting female
Siren - 5/6 chance of getting male, 1/6 chance of getting female
Pixie - 1/3 chance of getting male, 1/3 chance of getting female, 1/3 chance of getting neither
Fairy - 1/3 chance of getting male, 1/3 chance of getting female, 1/3 chance of getting neither

1/3 chance male, 1/3 chance female, 1/3 chance neither
+ 1/3 m, 1/3 f, 1/3 n = 1/3 m, 1/3 f, 1/3 n
+ 1/2 m, 1/2 f = 5/12 m, 5/12 f, 2/12 n
+ 5/6 m, 1/6 f = 7/12 m, 3/12 f, 2/12 n
+ 1/6 m, 5/6 f = 3/12 f, 7/12 f, 2/12 n

1/2 change male, 1/2 chance female
+ 1/3m, 1/3f, 1/3n = 5/12m, 5/12f, 2/12n
+ 1/2m, 1/2f = 1/2m, 1/2f
+ 5/6m, 1/6f = 8/12m, 4/12f
+ 1/6m, 5/6f = 4/12m, 8/12f

5/6 chance of male, 1/6 chance of female
+ 1/3m, 1/3f, 1/3n = 7/12m, 3/12f, 2/12n
+ 1/2m, 1/2f = 8/12m, 4/12f
+ 5/6m, 1/6f = 5/6m, 1/6f
+ 1/6m, 5/6f = 1/2m, 1/2f

1/6 chance of male, 5/6 chance of female
+ 1/3m, 1/3f, 1/3n = 3/12m, 7/12f, 2/12n
+ 1/2m, 1/2f = 4/12m, 8/12f
+ 5/6m, 1/6f = 1/2m, 1/2f
+ 1/6m, 5/6f = 1/6m, 5/6f