If Jesus has blood siblings, why did He leave His mother to John, the Beloved Apostle?
"Ah, so this is the standard Catholic position? That the term used for "brother" could mean cousin, etc.? Jesus must have been an only child?"
There was another theory also adopted by some of the Fathers (more prevalent among the Greeks). They said that St. Joseph was a widower when he married the Mother of God, and that he had children by that former marriage - Mary was their step-mother.
Whichever theory that they held, however, the Fathers were unanimous that the Blessed Virgin remained so after the birth of Jesus and consequently bore no other children herself.
Jesus had no other siblings. The term used for "brother" can mean cousin etc.
Our Lady, from the very instant of her existance in the womb of her mother, was concieved without the stain of sin (known as "original sin" or "the sin of Adam") because although every other person that is born into this world has the sin of Adam handed down to them by their parents, for God's purpose and by His will, God spared Mary of this sin due to the impending position that She was to partake of later in life, hence, any child that She would have bore would not have had the necessary ingredient to be born in original sin because She was not born in original sin, therefore the sin itself nor its effects could be handed down to Her child.
There's been something I've been ruminating over, perhaps some of you can contribute your thoughts so bear with me a moment. As Stubborn stated, the "brethren of the Lord", though Greek "adelphoi", is believed to be a literal translation of whatever the Aramaic/Hebrew is for brother, with its wider semantic application (brother, cousin, etc.).
However, in apologetics I've also used the argument that when the translators of the Septuagint translated "alma" from the Hebrew (which can mean virgin or maiden), they translated it specifically as "parthenos" which means "virgin". Their translation, then, was a key to the original intent of the passage: namely, when they were permitted to use a language that actually *had* the semantic distinction, they made use of it. If they hadn't used it, and just used a word that meant "maiden", it could be argued that they were showing that no literal virginity was implied in the passage.
Aren't the alma and "brothers of the Lord" argument mutually exclusive? That is, if the LXX translators chose the best Greek word to fit the Hebrew *intent*, and not necessary the literal word, why would the Gospel writers not have done the same and used the Greek word for "cousin" instead of "brother". I suppose you can argue it's a Semiticism...and TantumErgo said it is common NT usage in post #12. But the whole thing rather confuses me, because at the face of it, it looks a bit a priori.
It's because of these difficulties that (despite being a staunch Latin) I tend more toward the Eastern tradition that St. Joseph had childred by a previous marriage. But I'm open to change my mind :) Just trying to shore up the apologetic here so as not to get caught with our pants down.