The Catholic church teaches the Perpetual Virginity of Mary. The perpetual virginity of Mary is the doctrine that Mary, the mother of Jesus Christ, was a virgin ante partum, in partu, et post partum—before, during and after the birth of Christ. It is one of the four Marian dogmas of the Catholic Church, and is held also by the Eastern Orthodox Churches in Eastern Christianity and by some Lutherans and Anglicans in Western Christianity.
Look at the following excerpt from the Catechism:
#499 The deepening of faith in the virginal motherhood led the Church to confess Mary's real and perpetual virginity even in the act of giving birth to the Son of God made man. In fact, Christ's birth "did not diminish his mother's virginal integrity but sanctified it." And so the liturgy of the Church celebrates Mary as Aeiparthenos, the "Ever-virgin".
While Mary was indeed a virgin when she gave birth to Jesus Christ, she had other sons and daughters according to the Bible.
Matt 13:55 Is not this the carpenter's son? is not his mother called Mary? and his brethren, James, and Joses, and Simon, and Judas? 56 And his sisters, are they not all with us? Whence then hath this man all these things?
The Catholics argue that these are his cousins, the children of another Mary:
#500 Against this doctrine the objection is sometimes raised that the Bible mentions brothers and sisters of Jesus. The Church has always understood these passages as not referring to other children of the Virgin Mary. In fact James and Joseph, "brothers of Jesus", are the sons of another Mary, a disciple of Christ, whom St. Matthew significantly calls "the other Mary". They are close relations of Jesus, according to an Old Testament expression.
However, a closer examination of the original Greek scripture puts all such speculations to rest. The Bible has instances where it mentions both “cousin brother” and “own brother”.
Col 4:10 Aristarchus my fellowprisoner... and Marcus, sister's son to Barnabas,(KJV)
Col 4:10 Aristarchus my fellow prisoner greets you, and Mark the cousin of Barnabas (concerning whom you have received instructions if he comes to you, welcome him) (ESV)
The original Greek scripture uses the word ἀνεψιός transliterated as “anepsios”.
It is a masculine noun which directly translates to “sister’s son” or “cousin” [Strong g431].
Origin: From G1 (as a particle of union) and an obsolete form νέπος nepos (a brood)
Now consider few examples where the Bible mentions “own brother”.
John 1:41 He first findeth his own brother Simon, and saith unto him, We have found the Messias, which is, being interpreted, the Christ.
Matt 4:18 And Jesus, walking by the sea of Galilee, saw two brethren, Simon called Peter, and Andrew his brother, casting a net into the sea: for they were fishers.
Matt 4:21 And going on from thence, he saw other two brethren, James the son of Zebedee, and John his brother, in a ship with Zebedee their father, mending their nets; and he called them.
For those people who argue that James and John had the same father but different mother, the following verse proves that they were literal blood brothers with the same set of parents.
Matt 20:20 Then came to him the mother of Zebedee's children with her sons, worshipping him, and desiring a certain thing of him. 21 And he said unto her, What wilt thou? She saith unto him, Grant that these my two sons may sit, the one on thy right hand, and the other on the left, in thy kingdom.
In all the above instances the original Greek scripture uses the word ἀδελφός transliterated as “adelphos”, meaning literal own brother. [Strong g80].
Having established that the word “adelphos” [g80] indicates “own brother”, we must carefully note that all the below verses use the same word to denote Jesus’ siblings:
Matt 13: 55 Is not this the carpenter's son? is not his mother called Mary? and his brethren, James, and Joses, and Simon, and Judas? 56 And his sisters, are they not all with us? Whence then hath this man all these things?
Mark 6:3 Is not this the carpenter, the son of Mary, the brother of James, and Joses, and of Juda, and Simon? and are not his sisters here with us? And they were offended at him.
Matt 12:47 Then one said unto him, Behold, thy mother and thy brethren stand without, desiring to speak with thee.
John 2:12 After this he went down to Capernaum, he, and his mother, and his brethren, and his disciples: and they continued there not many days.
Acts 1:14 These all continued with one accord in prayer and supplication, with the women, and Mary the mother of Jesus, and with his brethren.
Gal 1:19But other of the apostles saw I none, save James the Lord's brother.
From all the above examples we can clearly see that Mary had other sons and daughters. She was a virgin only until Jesus’ birth.
Matt 1:25 And knew her not till she had brought forth her firstborn son: and he called his name JESUS.
So, any attempt to portray Mary as “Perpetual Virgin” or “Eternal Virgin” is unbiblical. She was indeed a righteous and virtuous woman. But it all ends there, As all other humans, she herself looked up to God for salvation:
Luke 1:46 And Mary said, My soul doth magnify the Lord, 47 And my spirit hath rejoiced in God my Saviour.
How pitiful and ridiculous it is when people look up to Mary for salvation and intercession? God is Sovereign. When Mary tried to “intercede” in the wedding of Cana, we see Jesus’ reply:
John 2:3 And when they ran out of wine, the mother of Jesus said to Him, “They have no wine.” 4 Jesus said to her, “Woman, what does your concern have to do with Me? My hour has not yet come.” 5 His mother said to the servants, “Whatever He says to you, do it.”
This is the lesson: “do what He says to do”. So, what does He say?
John 10:9 I am the door: by me if any man enter in, he shall be saved, and shall go in and out, and find pasture.
John 14:6 I am the way, the truth, and the life: no man cometh unto the Father, but by me.
The Lord Jesus Christ has already granted us direct access to His throne. We have no need of any other human intercessor or mediator. Amen.