Conversation so far:
How many times did Harriet Tubman get married?
Harriet Tubman was married twice.
When did she get married to John Tubman?
Around 1844, Harriet Tubman married a free black man named John Tubman.

Question: How many children did they have?
Self-contained rewrite: How many children did Harriet Tubman and John Tubman have?