The implication, of course, is that we must be in danger of incorrect doctrine because we don't have a pastor in the traditional sense. This is just silly. Numerous churches have blasphemous doctrine and also have traditional pastors.
When we look in Acts 20 we see Paul charge the elders from the church in Ephesus to protect the flock from false teachers. Therefore, the older men in any church family do bear some responsibility in defending the gospel. However, Paul never says that only the elders have this responsibility.
As Christians we are all priests to God. This is a dual gift and responsibility. As part of mutual edification, we should care deeply that each member of the church family holds correct beliefs about the gospel. Directly related to this, we must look out for each other in our relationships with Christ.
I know how I plan to answer the next time I'm asked who makes sure we have correct doctrine. I'm simply going to say, "We all do."