Was Mary born sinless?
Did she remain sinless?
There is nothing written in the Bible that says that Mary was born of an Immaculate Conception.
There is nothing written in the Bible which states that Mary was always a virgin and that her marriage with Joseph was never consummated.
The Bible does mention that Jesus had brothers and sisters.
Yes!
**Was Mary born sinless?**
No.
“..God sending his own Son in the likeness of sinful flesh, and FOR sin, condemned sin in the flesh’. Rom. 8:3
God “hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.” 2Cor. 5:21
Jesus Christ took on your sin, my sin, and......even Mary’s sin.
Here are some thoughts on the subject from early Christians:
http://www.staycatholic.com/ecf_immaculate_conception.htm