Yes I know about this. A whole cottage industry developed around the 4th and 5th centuries which tried to develop the theory or the notion that Mary and Joseph never consummated their marriage. There is mention of Jesus’s brothers and sisters in at least three of the four Gospels, Matthew, John, and Mark. The Gospel of Luke mentions that Jesus was Mary’s first born son and that Mary was a virgin at the time of her conception of Jesus. There is no mention that she always remained a virgin or that she and Joseph were denied the gift of marital intimacy-—which some seem to regard as something dirty or some sort of defilement.
I first learned that Jesus had brothers and sisters in a bible study class which-—btw-—was taught by a Catholic priest in a Catholic Church. Fortunately the priest taught the Bible precisely as it is written. He did not try to same something like, oh those brothers and sisters you are reading about in the Gospels are really Jesus’s cousins-—or another whopper-—oh they are Joseph’s children from an earlier marriage. It is wrong to twist words and meanings in the Bible. It is wrong to make things up or to speculate or hypothesize something just to make it fit into some sort of doctrine, dogma, or ideology. It is better to read the Bible as it is written and not try to read things into it which aren’t there.
God Bless. Merry Christmas and Happy New Year.