Yes, I really have heard that objection. But there are many ways people cast doubt on the Bible. It's a huge subject, and it can become technical pretty fast. But here are two things to keep in mind as we interact with our friends.
One, the Bible did not come down to us the way some people think –- like the game when one person whispers a secret to the next person, than that person to the next, around the circle until the final person reveals how crazily distorted the original message had become. The New Testament was preserved along many lines of transmission, unlike that one circle of people, and copying the Bible was no game to anyone involved. The United Bible Societies edition of the Greek New Testament lists hundreds of manuscript evidences, a few dating as far back as the second and third centuries. By contrast, the Loeb edition of Aristotle's Metaphysics is mostly derived from five manuscripts, the best of which dates to the tenth century A.D., about 1300 years after Aristotle. This is why Bruce Metzger, an expert in the field, says, "The textual critic of the New Testament is embarrassed by the wealth of his material" (The Text of the New Testament, second edition, page 34). We don't have to re-create a lost New Testament.
And in the Old Testament, the Dead Sea Scrolls confirm that the Masoretic Text of the Hebrew Bible, though medieval in date, was carefully preserved. The scribes obsessed about accuracy. Take Isaiah. There are thousands of words in Isaiah. But the Revised Standard Version of 1952, which had no axe to grind for a conservative view of the Bible, decided for a wording in the Dead Sea Scrolls Isaiah against the Masoretic Isaiah in only around 15 cases. Why? The traditional text is a convincing witness to antiquity.
Two, consider what Jesus thought of the Bible – in his day, the Old Testament. Jesus said, "The Scripture cannot be broken" (John 10:35). In other words, "The Bible cannot be proven wrong." Jesus never breathed the slightest hint of doubt about the Bible. In fact, he affirmed it repeatedly, including some of the hard-to-accept parts, like Jonah and the whale (Matthew 12:40). John W. Wenham summarizes Jesus' view of the Bible: "To him, what Scripture said, God said" (Christ and the Bible, page 37). If we respect Jesus enough to believe him about other things, why would we refuse him here?
Some will object, "But everybody back in Jesus' world believed that. He was a man of his times. We know better now." Do we? Isn't our skepticism a function of our own times? What's so striking about Jesus is how unlike his times he was. That's what got him crucified. Let's not patronize Jesus. He was a competent thinker for all times. He was speaking from God. He demonstrated a wisdom that – if we'd accept it today – would advance our thinking on all the most important fronts. What if suddenly we all believed everything Jesus taught? Would that be so bad?