Let’s hope Congress does not flinch as it begins the debate about immigration reform because the future is passing through security – in the wrong direction. It leaves the United States on every departing airplane carrying a foreign born student who has graduated from an American university with an advanced degree in the sciences, technology, engineering and math. The majority of these people want to stay in the United States but because of existing immigration laws, they have no choice but to leave.

In Silicon Valley, which has always been blind to any attribute other than ability, everyone knows that the remarkable achievements of the foreign born have led to the formation of companies such as Google, Intel, Sun Microsystems, nVidia, Yahoo! PayPal and scores of others that are less well known. Of the last eleven early stage companies that have allied themselves with Sequoia Capital, seven have had immigrants among their founding lineup. This is not a sudden or recent phenomenon; it has been the leitmotif of our business since the 1970s. However, the number of startups would be even higher if we weren’t ejecting foreign-born students and if we welcomed their contemporaries who have been educated overseas. Today, it is impossible to satisfy Silicon Valley’s appetite for engineers and scientists with people born in America.

Editor’s note: This is a guest post on TechCrunch by Greg McAdoo. Greg’s interests include collaborative consumption, the cloud infrastruture and the post-PC era. He currently works with companies like Airbnb, Bump, Songkick and Y Combinator

Tomorrow hundreds will meet up for Startup School, YC’s annual event for gutsy hackers thinking about founding a company. It’s one of my favorite events, and this year’s attendees will get to hear from everyone from Mark Zuckerberg to Stripe’s Patrick Collison to Weebly’s David Rusenko. It’s oversubscribed again, so here are some thoughts on how to choose an idea for your startup for those who can’t make it.

Investors always tell you to pursue big ideas, find your passion and iterate rapidly.That’s valuable advice, but there are some other important considerations that you don’t hear very often: tackle a small market, look for bizarre behavior, don’t make waves, and be unwilling to do anything else. Paul Graham also has some helpful suggestions here and here.