Genesis Framework vs. Child Themes

Think of the framework as the Parent or main theme. It could be run just with that but...
Genesis is a pretty powerful framework/theme and they rely heavily on using child themes for many reasons.
A child theme allows you to take advantage of all the parent theme (framework) power and functions without making a single change to the core theme (framework). Everything can be changed, filtered or overridden by a child theme.
If your going to run genesis, have the framework, but use a child theme to design and modify your site.

Straight from the horses mouth......the Genesis explanation

One disadvantage to just using the parent theme is most changes and careful modifications will be overridden when you update the theme. If your an experienced developer, no big deal, implementing the updates is not too hard.
The advantage to using a child theme, (especially non-developers) is that all your hard work and hours of modifications are preserved when you update the main theme.
As far as updating, you really need to do that. WordPress makes some significant changes every year and if your holding back on the theme update, you'll have to hold back on the WP update as well.

As mentioned above, first you need to understand what is child theme here http://codex.wordpress.org/child_themes

Genesis framework is a term use by StudioPress that identical to Parent Theme. ThEire frameworks already have many functions built in, so we would find it easier to reduce amount of time to produce a new child themes based on their framework or parent theme.

While WordPress normally upgrade their versions to reduce risk of security, all themes itselves need to comply with WordPress core practice, so we could update our parent themes easily without affecting child theme style and look.

But, the article here at beginner would suit your questions much http://wpbeginner.com/beginners-guid...heme-framework