For most of her life, children’s author and illustrator Kate Pankhurst had no idea she was distantly related to Emmeline Pankhurst, and a cousin of the suffragette’s direct descendants. “I was in my 20s when I found out about our family connection, but because of my surname, Emmeline’s story has followed me all my life, and my awareness of her struggle and what she stood for has been an influence on my work.”

Now, 100 years after the suffragettes won some women the vote, Pankhurst’s picture book Fantastically Great Women Who Changed the World is to be celebrated at this week’s Imagine Children’s Festival at London’s Southbank Centre. The book pays tribute to Emmeline and 13 other notable women, such as Amelia Earhart, Mary Anning, Marie Curie and Rosa Parks, and is aimed at children as young as five.

“There’s such a need to tell these stories and celebrate these women. It offers a way for parents to talk about gender equality – quite a hard subject to discuss with young children – and how, although we are moving towards more equality, there are still differences out there and challenges girls in particular may face. At the end, it asks the reader: how will you change the world?”

Qiu Jin, the Chinese poet, intellectual and activist, was executed in 1907 for taking part in a failed uprising against the Qing dynasty. Illustrated by Kate Pankhurst for her book Fantastically Great Women Who Made History. Photograph: © Kate Pankhurst

Demand for the book – which has sold more than 100,000 copies, been translated into 15 languages and nominated by librarians throughout the UK for the Kate Greenaway Medal 2018 – took publisher Bloomsbury by surprise last year. “We knew that Fantastically Great Women was something special and timely, but we’ve been blown away by its success,” said Liz Skelly of Bloomsbury. “From comments on social media and mixed gender attendance at school and public events, it has been great to see that parents are buying the book for boys as well as girls.”

For Pankhurst, the gap in the market was obvious. “As far as I could see, there weren’t any nonfiction books celebrating women for five- to nine- year-olds. And I found myself wondering: why doesn’t that book exist already? It seemed a bit bonkers.”

But even she has been surprised by how popular the book has been and how outraged children are when they read about women being treated unfairly. “Parents tell me it’s a good conversation starter. It gives children a way to understand the past, talk about the way things are now and how to move forwards, and it gives parents a way to discuss the injustices of the past with young children. I didn’t anticipate how much parents want to have these conversations with their sons and their daughters.”

Her second book in the series, Fantastically Great Women Who Made History, was published last Thursday and features another suffragette, Flora Drummond, as well as Harriet Tubman, Boudicca and Ada Lovelace.

“These are women from different cultures and backgrounds who have thrown off gender stereotypes to achieve amazing things,” says Pankhurst. “It was really important to me to expose both boys and girls to these role models and to share a message about aspiration. Because as a child, what you see in books conveys a powerful message. It shapes you as a person.”

She was dismayed to read the research carried out by the Observer last month, which found male characters dominating the top 100 bestselling picture books last year, and far more likely to be heroes, villains and powerful animals than female characters (who spoke less often and were often in supportive, nurturing roles). “It’s shocking how entrenched these things are in society. Repeatedly reading books where boys are one type of character and girls another must have a powerful drip-feed effect.”

She says some older boys will assume her book isn’t aimed at them. “On the other hand, it’s exciting to be an author and illustrator at a time when we’re questioning why that is.”

Kate Pankhurst is part of People Who Changed the World at the Southbank Centre’s Imagine Children’s Festival on 13 February.

Fantastically Great Women Who Changed The World by Kate Pankhurst (Bloomsbury Childrens Books, £7.99). To order a copy for £6.79, go to guardianbookshop.com or call 0330 333 6846. Free UK p&p on orders of more than £10, online orders only. Phone orders min. p&p of £1.99.

Fantastically Great Women Who Made History by Kate Pankhurst (Bloomsbury Childrens Books, £11.99). To order a copy for £9.99, go to guardianbookshop.com or call 0330 333 6846. Free UK p&p on orders of more than £10, online orders only. Phone orders min. p&p of £1.99.