Sentence:  Her mother wrote Kate of her grief at the death of Kate 's baby and at Jonathan 's decision to go with the South `` And , dear Kate '' , she wrote , `` poor Dr. Breckenridge 's <WSD>son</WSD> Robert is now organizing a militia company to go South , to his good father 's sorrow . 
Meaning of the word marked with <WSD> tags:  a male human offspring