Missionary’s kids (or MKs) are the children of missionary parents, and thus born or raised abroad (that is, on the "mission-field"). They form a subset of third culture kids (TCKs). The term is more specifically applied when these children return to their "home" or passport country (the country of their citizenship), and often experience various difficulties identifying with fellow citizens and integrating "back" into their "home" culture. The resulting feeling is described as "reverse culture shock". There is some confusion between the terms MK and TCK. According to the definition developed by Ruth Hill Useem, TCKs are people who have spent a significant part of their developmental years outside their parents' culture. TCK is a broad term that encompasses all children who have grown up abroad (i.e. military kids, diplomats' kids, immigrants). Missionary kids are just one of the many categories of kids who qualify as TCKs. Therefore, while all MKs are TCKs, not all TCKs are MKs. In the past MKs usually were thought of only as American or European, but there is a growing number of MKs from other countries, especially Protestant Christian MKs from South Korea and from Latin America. Generally, this term applies to Protestant Christians; however, it can be applied to any denomination of a religion. Definition Life overseas While MKs often identify more with the culture or country where they were raised (and this could be multiple cities, countries, or continents) than with where their parents were raised, they are not fully at home in any one culture. David C. Pollock and Van Reken attribute this feeling of displacement, or rootlessness, to a lack of emotional connection to their home culture (where they "should" feel connected). Many MKs find it difficult to answer questions about where they are from or where home is as they may feel more of an emotional connection to their host culture than to their "home" culture. However, at the same time many MKs are completely aware that they can never fully fit into their host culture. This is especially obvious to MKs growing up in countries where they look different from the local population. Pollock and Van Reken developed the PolVan Cultural Identity Model to explain cultural identity in relationship to the surrounding culture. The Model names four categories into which a person can fall based on how they look and think compared to the culture around them: Foreigner