know one another and be comfortable in each others' company, and parallel polyamory, with relationships between people who are kept separately, all may be aware of each other, but are not expected to be friends. There is also group marriage, where several people form a single familial unit and each person considered to be married to all other members. Line families are a form of group marriage intended to outlive its original members by ongoing addition of new spouses and poly families, which is similar to group marriage, but some members may not consider themselves married to all other members. Favorable preexisting conditions before non-monogamy Michael Shernoff cites two studies in his report on same-sex couples considering non-monogamy. Morin (1999) stated that a couple has a very good chance of adjusting to non-exclusivity if at least some of the following conditions exist. This includes both partners wanting their relationship to remain primary, the couple having an established reservoir of good will, and a minimum of lingering resentments from past hurts and betrayals. Other conditions include the partners in agreement on the question of monogamy/non-monogamy and the partners feeling similarly powerful and autonomous. Additionally, Green and Mitchell (2002) stated that direct discussion of the following issues can provide the basis for honest and important conversations, including openness versus secrecy, volition and equality versus coercion and inequality. Other issues include clarity and specificity of agreements versus confusion/vagueness, honoring keeping agreements versus violating them, and how each partner views non-monogamy. According to Shernoff, if the matter is discussed with a third party, such as a therapist, the task of the therapist is to "engage couples in conversations that let them decide for themselves whether sexual exclusivity or non-exclusivity is functional or dysfunctional for the relationship." Public health and morality The concepts of monogamy and marriage have been strongly intertwined for centuries, and in English-language dictionaries one is often used to define the other, as when "monogamy" is "being married to one person at a time." A common antonym is polygamy, meaning to have more than one spouse at one time. As a result, monogamy is deeply entrenched within many religions, and in social regulations and law, and exceptions are condemned as incursions on both morality and public health. To some, the term non-monogamy semantically implies that monogamy is the norm, with other forms of relational intimacy being deviant and therefore somehow unhealthy or