1. GENDERS: Females are represented by a circle and males are represented by a square. 

2.  A horizontal line between a circle and square represents a marriage/mating. 

3. Children or offspring of parents are shown at the bottom of a line extending from the marriage/mating line. 

4. Generations are represented by Roman Numerals (I, II, III) and individuals are represented by Arabic numbers (1, 2, 3)

5. A shaded circle or square indicates a person who has the trait of interest. 

6. A half-shaded circle or square indicates a person who is a carrier but does not actually exhibit the trait themself. (Some pedigrees don't half shade though so you may have to infer who is just a carrier by looking at the offspring.)

Remember: Autosomal disorders are conditions involving chromosome pairs 1-22. and sex-linked disorders only involve the X chromosome (unless indicated otherwise).