I have read two books recently about a possible child of the very young Elizabeth Tudor, soon to become Queen Elizabeth I. The first is The Lady Elizabeth by Alison Weir.
Ms. Weir has done considerable research on Henry VIII and his children, but this is a book of fiction concerning the life of the young Elizabeth. The major focus of the book is the fine line the young heir walks between obscurity and being the heir to the British Throne. Central to the book is the possibility the she bore a child when she was about 14, courtesy of Thomas Seymour.
What is amazing about this story is the shrewdness of the young Elizabeth and her uncanny understanding of politics. Much is because of her outstanding intelligence and composure. While the subject of Elizabeth I has been covered innumerable times, this book has found a way to be fresh and interesting.
The second is The Virgin Queen's Daughter by Ella March Chase.
Continuing on the idea that the young Lady Elizabeth did have a child when she was barely 14, the story is written through the eyes of that daughter. Her position is fraught with danger and intrigue. Despite her mother's protests, Elinor de Lacey schemes to get summoned to court where she finds out that she is the daughter of the queen. At first Elizabeth is enchanted by her, but as time goes on, she begins to suspect that there may be more to Elinor, and that she could be a threat to her reign. The court intrigues are fascinating and the story is well written.