2014, Line Nybro Petersen, "Sherlock fans talk: Mediatized talk on tumblr", Northern Lights, Volume 12, Number 1, June 2014, page 94:
In this way, the blog post inscribes itself in the fan-made slash fiction discourse that romantically pairs Sherlock and John (Johnlock fan fiction), and a subcategory of these fan fiction stories are concerned with John and Sherlock being parents (typically named Parentlock).
2016, Alyxis Smith, "Fan Fiction as an Argument: Arguing for Johnlock through the Roles of Women and Explicit Sex Scenes in Sherlock Fan Fiction", in Who Is Sherlock?: Essays on Identity in Modern Holmes Adaptations (ed. Lynnette Porter), page 164:
Especially because of Season Three's depiction of heavily pregnant Mary in "His Last Vow," fans who ship Johnlock are more likely to consider the inclusion of a Watson baby within the parentlock narrative of Sherlock and John.
2017, Judith May Fathallah, Fanfiction and the Author: How Fanfic Changes Popular Cultural Texts, page 65:
The relevant tags here were very similar to LJ, if phrased slightly differently: e.g., parentlock (portmanteau of parent + Sherlock), military John, genderswap, mpreg.
2018, Jennifer Wojton & Lynnette Porter, Sherlock and Digital Fandom: The Meeting of Creativity, Community and Advocacy, page 41:
All of these AU parentlock stories or series become "alternate" because of a change in the Sherlock-John relationship and the inclusion of a child who becomes theirs.