Ulrichs is recognized today as a pioneer of the modern gay rights movement. He also championed the promotion of Living Latin. His writings sought to understand and advocate for individuals with non-normative sexual orientations during a time when such matters were highly stigmatized. His commitment to openness and the advancement of rights laid foundational groundwork for future generations of activists and thinkers.
Surveys literary, historical, physiological, and other data and argues that homosexuality is not a disease or a sin, but perfectly natural. This book contends that male, as well as female, homosexuality results from a crossing of the male and female generative principles during the first crucial stages of foetal development.