Discrimination by start-ups is enshrined in law. If you are a racist, you don't like old people, or you don't like Jews - no problem until you have 15 employees.

Fire your pregnant employees at will, crack down on sodomy - the start-up world is your discriminatory oyster: http://www.eeoc.gov/employers/coverage_private.cfm

California does have a law that tightens things up a bit, called FEHA. You only need 5 employees in California before you need to start treating people as you should: http://mccabeconsultants.com/forms/ADA%20Chart.pdf

I kid a bit in this post, but the limits on these laws are a two-edged sword. I think small companies can be crippled by pregnancies, and having the threat of a lawsuit about age discrimination can mess with your mind on hiring the right people. You can also imagine that a Hacedic markets should be run by Hacedic Jews. But there is certainly some amount of bad consequences from the limits on these laws, and a few too many white people running start-ups.