Anisogamy is the ratio of the size of male and female gametes, that can explain the main aspects of sex differences. In our study, we investigated the relationship between anisogamy and various reproductive traits, such as SSD, mating systems, parental care, and clutch size and volume. The prediction was that anisogamy is associated with clutch size and clutch volume and not linked to SSD, mating systems, and parental care. The PGLS analysis did not reveal a significant correlation between any of these variables.