Children are increasingly accessing social media content through mobile devices. Existing data protection regulations have focused on defining the digital age of consent, in order to limit collection of children's personal data by organizations. However, children can easily bypass the mechanisms adopted by apps to verify their age, and thereby be exposed to privacy and safety threats. We conducted a study to identify how the top 10 social and communication apps among underage users apply age limits in their Terms of Use. We also assess the robustness of the mechanisms these apps put in place to verify the age of their users. Moreover, we discuss how automated age recognition techniques can be adopted to increase the effectiveness of the age verification process. Finally, we provide recommendations to app providers and developers to specify the Terms of Use and implement robust age verification mechanisms.