Even as House Republicans press to repeal the healthcare law, government advisers this week are preparing to wade into one of the most contentious questions raised by the legislation: What benefits must insurers cover? The answer will affect tens of millions of Americans beginning in 2014: those who buy their own insurance and those who get coverage through small employers. While the law outlines 10 broad categories of coverage — among them hospital and emergency services, prescription drugs, childbirth and pediatric care — it leaves the specifics to the government. The Obama administration faces a tough balancing act: the benefits package must be broad enough to be comprehensive but not too broad as to be unaffordable. Patient advocates and industry lobbyists already are drawing up wish lists for items they want covered — including autism therapy, obesity treatments, infertility treatments and unlimited chemotherapy visits.