Conversation so far:
What political topics was Charles Bradlaugh interested in?
Bradlaugh was an advocate of trade unionism, republicanism, and universal suffrage, and he opposed socialism.
Why did Charles Bradlaugh become an activist?
Bradlaugh returned to London in 1853. By this time he was a convinced freethinker. He gradually attained prominence in a number of liberal or radical political groups or societies.
What years was Charles Bradlaugh writing about his freethinking ideas?
Bradlaugh returned to London in 1853. By this time he became a pamphleteer and writer about secularist ideas, adopting the pseudonym Iconoclast to protect his employer's reputation.
Did Charles Bradlaugh write all the articles himself or were there other writers also?
1876, Bradlaugh and Besant decided to republish the American Charles Knowlton's pamphlet advocating birth control, The Fruits of Philosophy, or the Private Companion of Young Married People
Did Charles Bradlaugh and Besant get in trouble with the authorities?
The two activists were both tried in 1877
Were Charles Bradlaugh and Besant found guilty for their pamphlet advocating birth control?
They were sentenced to heavy fines and six months' imprisonment, but their conviction was overturned by the Court of Appeal.

Question: What is another topic besides birth control that he wrote about?
Self-contained rewrite: What is another topic besides birth control Charles Bradlaugh wrote about?