Mammalian sperm need to undergo capacitation to become competent to fertilise the oocyte. In vivo, this occurs in the female reproductive tract, whereas in vitro it can be triggered by culture in defined media. One of the key events during capacitation is cAMP-dependent tyrosine phosphorylation of various proteins. Although this phenomenon has been well described in many species, the kinase responsible has been elusive. Various candidates have been proposed, including SRC, FAK and PYK2; notably, inhibitors for the latter two enzymes block tyrosine phosphorylation in human and horse sperm. However, definitive evidence for the identity of the kinase has been lacking. Now (p. 2325), Pablo Visconti and co-workers show that, while FAK and PYK2 inhibitors also block tyrosine phosphorylation in mouse sperm (without blocking PKA activation), neither is the responsible factor. Instead, it is the FER kinase – also targeted by the same inhibitors – that carries out capacitation-associated tyrosine phosphorylation. However, and surprisingly, FER is not required for fertilisation in vivo, suggesting that the presumed involvement of tyrosine phosphorylation in acquisition of sperm competence may need to be revisited.