Sam Altman, the 31-year-old president of the wildly successful startup accelerator Y Combinator, published an essay on Monday in which he attempted to address the mounting concerns over his company's ties to Silicon Valley billionaire and Donald Trump delegate Peter Thiel. The company's relationship with Thiel, who serves as an unpaid part-time partner and recently donated $US1.25 ($2) million in support of Trump, has already led the pro-diversity group Project Include to disavow Y Combinator. Yet Altman insists that any action against Thiel (such as firing him from the company) would be "a dangerous path to start down."