“…Other evidence suggests that other hormones, like prolactin and oxytocin (see Gordon, Zagoory-Sharon, Leckman, & Feldman, 2010), play a role in paternal behavior similar to the role these hormones play in maternal behavior (e.g., Uvnäs-Mobcrg, Widström, Nissen, & Björvell, 1990). Furthermore, maternal behavior is associated (p. 436) with estradiol and progesterone, and their ratio, during gestation (e.g., Glynn, Davis, Sandman, & Goldberg, 2016), but their influence in male paternal behavior is unexplored in humans. The independent and interdependent effects of these hormones on parenting and other social behaviors, including social bond paradoxes (i.e., the seemingly contradictory activating function of certain hormones when applied to different circumstances, such as nurturing vs. infant-defense parenting behaviors; see Witczak, Simmons, & Bales, this volume), deserves additional attention.…”