One of those amendments could be a sticking point for the bill's supporters.
Del. Tag Greason (R-Loudon County) sponsored the autism bill. He says it's difficult for Virginia's autism community to feel satisfied right now, even though his bill has made it farther than any autism-related legislation proposed in recent years.
"Any time we can progress the awareness of the disorder and move the ball forward, we should feel good about that, but it does feel a little bit empty," he says.
Greason says that's because his bill left the governor's desk with a proposed amendment that puts it in serious risk.
As written, the law mandates $35,000 for health insurance coverage for autism-related treatments for children ages 2 to 6.
One of the governor's amendments says the law would be invalidated if "a court of competent jurisdiction" finds that $35,000 cap unenforceable. Greason says that means any district judge in the state could wipe away the law at any time.
"And that is a really, really difficult position to be in and we can't accept that," Greason says.
Greason and his supporters will need a two-thirds majority in each house to reject McDonnell's amendments.