This was a voluntary project for social studies class back when I was in the 7th grade around 1977. It was fun and interesting. On the other hand, my niece had a project last year of recording all her relatives genetic traits (eye color, hair color, right hand/left hand use, proportional finger length, ear lobe connectivity). It was interesting... but a little creepy.
We did not have to go back many generations. It was basically to see how dominant and recessive traits were expressed through a couple of generations. We also had to, based on what we figured our genotype to be, add a future spouse to our tree with the opposite genotype to ours and determine the probability of having children with certain phenotypes. It was a fine assignment in an era when stable families were more the norm. What I found funny was that my dad, whose parents had died years before, could not remember their eye color, which is a trait I always notice!