First, the Gospels are historical in genre (not myth); and they are shown to be reliable, based on eyewitness accounts, and confirmed by loads of other ancient documents. (See my bibliography on the historical reliability of the New Testament.)
Second, there are no good parallels to the Gospels that are older than the Gospels. (See the bibliography below.)
Third, even if there were older mythical or fictional parallels to the Gospels, that would still not mean that they are fictional. (See Michael Licona's excellent 2-minute video and a brief Wikipedia article laying this out in print. Or see this excellent spoof on the idea...which proves that Isaac Newton did not exist!)
Click on the title links to find the great resources listed below
(and then check out my growing MASTER LIST OF APOLOGETIC RESOURCES)....
*Lutheran Satire. "Horus Ruins Christmas." (5 minutes) A hilarious debunking of the claim that Jesus is based on the pagan Egyptian god Horus...or Mithras...or....
*Sharp, Mary Jo. "Challenge: Did Jesus Exist?" (6 minutes)
*Craig, William Lane. "Did Greco-Roman Myths About Dying and Rising Gods Influence the Gospel Accounts about the Resurrection?"
*Inspiring Philosophy. "Jesus vs. Horus" (4 minutes)
*Inspiring Philosophy. "Jesus vs. Krishna" (5 1/2 minutes)
*Sharp, Mary Jo. "Is The Story of Jesus Just Like Horus?" The "One Minute Apologist" interviews Mary Jo Sharp. (under 2 minutes)
*Wallace, J. Warner Wallace. "Is Jesus a Copycat Savior?" The "One Minute Apologist" interviews famous L.A. cold-case detective, J. Warner Wallace. (under 4 minutes)
Articles (& Book Chapters)
*Strobel, Lee and Edwin Yamauchi. Q & A on BibleGateway. Popular apologist and award-winning legal journalist Lee Strobel responds to a question by presenting a concise version of his interview with expert historian Edwin Yamauchi (based on a chapter from Strobel's book The Case for The Real Jesus. (Listen to the audiobook version of the book for FREE!)
*Komoszewski, J. Ed, M. James Sawyer, and Daniel B. Wallace. Reinventing Jesus, "Part 5: Stealing Thunder: Did Christianity Rip Off Mythical Gods?", pages 219-258.
*Del Rosario, Mikel. "Was Jesus' Death and Resurrection Copied from Krishna?"
*Sharp, Mary Jo. Lecture from SALT 2013 conference. (40 minutes)
*Nash, Ronald. "Was the New Testament Influenced by Pagan Religions?"
*Marshall, David: "Bart Ehrman Finds Jesus in Poland (Baal Shem Tov)"
*Marshall, David. "Bart Ehrman Scams His Students (Jesus vs. Apollonius of Tyana)"
*Miller, Glenn. "Was Jesus Christ Just a CopyCat Savior Myth?"
*"Jesus Christ and Mythology: Copy Cat Savior?" In spite of some occasional typos, this article offers some excellent corrections and information.
*Evidence for Jesus and Parallel Pagan "Crucified Saviors" Examined
*McIlhenny, Albert. Cut and Paste Jesus: Is Jesus a Copy of Other Gods?: by one of the foremost experts on Jesus mythicism
*Nash, Ronald. The Gospel and the Greeks: Did the New Testament Borrow from Pagan Thought?
*Strobel, Lee. The Case for The Real Jesus. Listen to the audiobook version of the book for FREE! In "Challenge #4" in this book, award-winning legal journalist Lee Strobel interviews expert historian Edwin Yamauchi on this issue (beginning on page 157).
*Marshall, David. Why the Jesus Seminar Can't Find Jesus, And Grandma Marshall Could. In the second section of this book, Marshall explores 50 characteristics of the Gospels; and in the third section, he uses these 50 characteristics to show how they are not at all like pagan myths or any of the other comparisons that have been made.
*Eddy, Paul Rhodes and Gregory Boyd. The Jesus Legend. Primarily about the historical evidence for Jesus but it does touch on the issue of pagan parallels.
*Porter, Stanley and Stephen J. Bedard. Unmasking the Pagan Christ.
RELATED PAGES ON MY BLOG
*So-Called Lost Gospels (Gnostic Writings)
*The Historical Reliability of the New Testament
*Archaeological Confirmation of the New Testament
*Undesigned Coincidences: A unique and underutilized internal evidence for the historicity of the Bible. I have tried to make this bibliography as exhaustive as possible.
*EhrmanProject.com. A collection of resources in response to popular skeptic Bart Ehrman. Also, see this,
*Contradictions in the Bible?: A list of several excellent resources for dealing with seeming contradictions in the Bible.
*The So-Called Synoptic Problem: A brief but helpful bibliography with a link to a more detailed bibliography.
*Check out this excellent bibliography from my friend Stephen J. Bedard, an expert on so-called pagan parallels and co-author of Unmasking the Pagan Christ....
OR....Another excellent list of resources by my friend Larry Lund....
OR....or this extensive list....
OR....the resource list at Christian CADRE.
Painting by Pieter Lastman (1616) Image Source