In a shrine where parent-child gods (Shito religion) are enshrined, the child god is called Mikogami or byoei-shin (descendant deity).
The word 'Mikogami' is used when both parent and child gods are chief gods and when the parent as the chief god and its child are enshrined together. In particular when mother-child gods are enshrined, it has something to do with the Boshi-jin shinko, belief in mother-child gods.
For example, Yasaka-jinja Shrine is dedicated to Susanoo (Deity in Japanese Mythology) in the center as the chief god, Kushinadahime as God Empress, Kisakigami on its east side and 'Yahashira-mikogami' on its west side. Kasuga-taisha Shrine has its 'Wakamiya-sha shrine' sessha (auxiliary shrine - dedicated to a deity close-related to that of a main shrine), which is dedicated to Amenooshikumone no mikoto, the Mikogami of its chief god, Amenokoyane no mikoto.
This 'Wakamiya,' which is often a shrine dedicated to the Mikogami of its chief god, means that not the dedicated god, but the shrine itself is young.
Shrines developed later are also called 'Wakamiya.'
In this case, some shrines are dedicated to the parent god as the chief god, or sosen shin (ancestral god), whereas others call otabisho (place where the sacred palanquin is lodged during a festival) or branch shrines Wakamiya. Therefore all Wakamiya are not dedicated to Mikogami.