I came to religion with practically no belief at all on any kind of doctrine, so I approach almost everything from this viewpoint.
When we read that Mary and Joseph were married and that Jesus had brothers and sisters, then the natural conclusion that anyone would make is that of course after the birth of Jesus they carried on as any married couple would.
To believe anything else requires believing things that are not apparent in scripture:
1. That Mary was always a virgin. Not to be indelicate, but the birth of Jesus would have shattered the physical sign of any virginity. I too have only a rudimentary grasp of Jewish society, but as I understand physical signs of viriginity in all cultures has always been the acid test of whether someone was virginal or not. Her physical purity would be the only outward sign to others that she actually had conceived and bore as a virgin. Once that was gone, through childbirth, then there would be no physical evidence that she was and thus no reason why they wouldn't have sex.
2. That Joseph was married before and had kids from a previous marriage. Again, in order to support the idea of perpetual virginity, an entire family history of Joseph that exists nowhere but in a belief has to be read into scripture.
3. That greek lacks a way to express "half-brother" or "cousin" and that the original writers of scripture were not expressing themselves exactly as they wanted.
These are the biggies. The only thing that gives me any pause is that Jesus turned over care to John instead of his brother. I don't doubt that this was rare in Jewish society, but I doubt that it was unheard of. From scripture, it's obvious that John and Jesus had a very close relationship, John refers to himself as "the disciple that Jesus loved" in John 21:7. Jesus also chose John to reveal the vision of end time prophecies to. The very act of turning over the care of Mary to him speaks volumes of their closeness.
The PVM thread that was locked has much information on this, as well as many resources on the Internet. You can read both sides of this and make an informed decision, which you want to do. I believe the belief in Mary as Ever-Virgin, is based in Scripture, with valuable information gleaned from Mosaic law at the time.
And being "apparent" to a first reading of Scripture is a necessity? If something is not absolutely contradicted by Scripture, can it still be believed?
1. That Mary was always a virgin. Not to be indelicate, but the birth of Jesus would have shattered the physical sign of any virginity. I too have only a rudimentary grasp of Jewish society, but as I understand physical signs of viriginity in all cultures has always been the acid test of whether someone was virginal or not. Her physical purity would be the only outward sign to others that she actually had conceived and bore as a virgin. Once that was gone, through childbirth, then there would be no physical evidence that she was and thus no reason why they wouldn't have sex.
Jesus' birth left Mary intact. It was miraculous. Secondly, virginity is not lost by childbirth. It is lost by intercourse. If a young woman loses her hymen through another manner (as many do) she is still a virgin if no man has entered her.
2. That Joseph was married before and had kids from a previous marriage. Again, in order to support the idea of perpetual virginity, an entire family history of Joseph that exists nowhere but in a belief has to be read into scripture.
Does Scripture tell you Joseph was not a widower? Does it tell you he was? Neither. Then accepting the idea is not contrary to Scripture. And the belief is ancient. And it is not read into Scripture, except for those who think Scripture is everything.
3. That greek lacks a way to express "half-brother" or "cousin" and that the original writers of scripture were not expressing themselves exactly as they wanted.
It is the Hebrew that lacks this wording. The Greek was expressing the idea that the Hebrews put forward. The original writers may not have thought that 1800 years later people would start to use their texts to deconstruct the stories that were passed down as true.
SD