They preach.
But barely teach it.
Except, we know Jesus has siblings.
So what happens to the bloodline?
You mean to tell the world that they didn't marry or have children.

We don't know.
No ministers seem to have that an answer.
Yes, like most they offer all speculative opinions about Christ relationship with Mary Magdelene.

Then, it's from written scriptures or taught logic they basing their views upon.

All most all males within scriptures according to the religious teachers of the word bloodline.
Can be traced?

But like Mother Mary and father Joseph they just background players lost in the substance of us wondering about his brothers and sisters.

Remember they lived in the flesh upon the earth.