Thanks for your questions.
No, there is no holy grail and no holy grail family and no such thing as a grail child. Jesus and Mary Magdalene were never married nor did they ever have a child. This notion is just silly superstition without even the faintest hint of real evidence. Read the Bible and leave this nonsense to those who are perishing in sin and folly.
I hope you have found this helpful.
God bless!
Mike
www.thisisyourbible.com