Did Mary Queen of Scots have any children?

Her only child was James VI/I

No legitimate ones. That was the whole problem! Actually, she had many siblings, but they were all bastards. Her brother James and her sister Jean (wife to the Earl of Agyle) are two of them.

yes a dog

Yes she did. She had many grandchildren. Her son James had nine children. The current Queen of England is a direct descentant of Mary, Queen of Scots.

One: James, born to Mary and her second husband, Henry Stuart, on 19 June 1566. He became King James I of England and Ireland and King James VI of Scotland.