A non-conversionary religion is any religion which either forbids or actively discourages the acceptance of converts from other religions. Many of these religions are often ethnically-identified, with their traditions being advanced hereditarily. As a result, the statuses of both spouses who are of another ethnic or religious background and the children of such "mixed" marriages are actively disputed within the contexts of these religion's views on inheritance.
In historical Judaism, converts are not actively sought, but are allowed to join, depending upon the speed of acceptance allowed by each denomination; Orthodox and Syrian Judaism tend to resist or prolong the conversion of non-Jews longer than Reform, Conservative, and other more liberal strands of Judaism. Outreach Judaism primarily limits activities to the non-Jewish spouses and children of mixed marriages, with greater emphasis being placed upon the conversion of female non-Jewish spouses for purpose of religious adherence.
Yazidis, Druze, and Mandaeans
Yazidis, Druze, and Mandaeans are often noted for the intense secrecy of their rituals, and do not actively seek or welcome converts from other religions.