What does the LDS Church teach about Jesus being married, having children, and His position on polygamy? In the Journal of Discourses, LDS apostles suggest that Jesus Himself was married, that He had children, and that He and His disciples endorsed polygamy.

It will be borne in mind that once on a time, there was a marriage in Cana of Galilee; and on a careful reading of that transaction, it will be discovered that no less a person than Jesus Christ was married on that occasion.  Journal of Discourses, Volume 4, Page 259
What did the old Prophet mean when he said (speaking of Christ), “He shall see his seed, prolong his days, &amp;c.” Did Jesus consider it necessary to fulfil every righteous command or requirement of his Father? He most certainly did. This be witnessed by submitting to baptism under the hands of John. “Thus it becometh us to fulfil all righteousness,” said he. Was it God's commandment to man, in the beginning, to multiply and replenish the earth? None can deny this, neither that it was a righteous command; for upon an obedience to this, depended the perpetuity of our race. Did Christ come to destroy the law or the Prophets, or to fulfil them? He came to fulfil. Did he multiply, and did he see his seed? Did he honor his Father's law by complying with it, or did he not? Others may do as they like, but I will not charge our Savior with neglect or transgression in this or any other duty.  Journal of Discourses, Volume 4, Page 260
The grand reason of the burst of public sentiment in anathemas upon Christ and his disciples, causing his crucifixion was evidently based upon polygamy, according to the testimony of the philosophers who rose in that age. A belief in the doctrine of a
plurality of wives caused the persecution of Jesus and his followers.   We might almost think they were &quot;Mormons&quot;.  Journal of Discourses, Volume 1, Page 346.

Was this ever the official teaching of the LDS Church?  If so, what biblical support for these doctrines is there?
Both @MaskedPlant and @Matt spelled out how the Journal of Discourses is viewed. 

I will add this; the only thing I have ever heard was during the whole "The Da Vinci Code" hoopla. And that was that the LDS church had no official opinion and that it neither endorsed or found fault with the ideas presented in that book. (Namely of course that Christ was married and had children). 

So the LDS church has no official teachings on the topic, but if it were to come to light that Christ was in fact married (or even had kids!), the LDS church would have no issue with that information.

Edit:
I found the official statement made by the church on this subject from 2006:


  "The belief that Christ was married has never been official Church doctrine. It is neither sanctioned nor taught by the Church. While it is true that a few Church leaders in the mid-1800s expressed their opinions on the matter, it was not then, and is not now, Church doctrine."


Link to the news article right here.

I believe that definitively answers your question and the issue of the Journal of Discourses.