This is a common response made by a lot of atheists who accuse the theist of special pleading when it comes to origins.
The theist will argue that the universe began to exist. Therefore, the universe has a cause. The implicit premise is that everything that begins to exist has a cause.
But notice that this isn’t special pleading. As the cause of all of space, time, matter, and energy, God would be timeless, spaceless, immaterial, uncaused, eternal, infinite, personal, and omnipotent in relation to the universe.
God did not have a beginning. Since God didn’t have a beginning, then obviously he does not need a cause!
Also when we speak of God, we speak of a necessary and self-existent being. In other words, God exists in every possible world, and it’s impossible for God to not exist. He must exist.