Conversation so far:
Did Havelock Ellis write any books about sexual impulse?
Havelock Ellis' 1933 book is one of the many manifestations of his interest in human sexuality.
What was the name of Havelock Ellis's 1933 book?
Havelock Ellis' 1933 book, Psychology of Sex, is one of the many manifestations of his interest in human sexuality.
What did Havelock Ellis say in the book Psychology of Sex?
In this book, Havelock Ellis goes into vivid detail of how children can experience sexuality differently in terms of time and intensity.

Question: What age approximately did he say that this impulse developed?
Self-contained rewrite: What age approximately did Havelock Ellis say that sexual impulse developed?