In our everyday experience, animals have two separate sexes. Some animals, and many plants, combine the two in a single individual but they still produce male and female gametes. This is such a basic generality that we become uneasy with the suggestion that there are many taxa (some of them mites, see Parthenogenesis) in which males are irrelevant (Fig. 5.1).
Walter, D. E., & Proctor, H. C. (2013). Sex and Celibacy. In Mites: Ecology, Evolution & Behaviour (pp. 105–159). Springer Netherlands. https://doi.org/10.1007/978-94-007-7164-2_5