  Instead of attempting to justify trans self-identity claims, Bettcher (2012a) argues, such claims ought to be accepted as presumptively valid as a starting-point of trans theory and politics (245-6). She adopts the general view that (many) trans people tend to oppose the meanings of mainstream gender terms and practices. In many trans subcultures, she argues, the meaning of terms such as woman and man are altered so that both trans men and trans women turn out to paradigm instances of men and women respectively (241). For example possession of XY chromosomes does not count against trans woman's claim to womanhood insofar as a trans woman is a kind of woman who tends to have XY chromosomes. As a consequence of this, an MTF may count as a man in mainstream culture while she may count as a woman in a resistant trans subculture (242). More deeply, Bettcher argues (2009, 110-12), the shift in meaning involves not only an expansion of the category, but also a change in use, reflected in the grammar of first and third person assertions. It is no longer merely a question whether the category is truthfully predicated of the object in question. Instead, there is a first person, present tense avowal of gender. For example, the claim “I am a trans woman” may be an avowal of a deep sense of “who one is” (that is, of one's deepest values and commitments) where defeasible avowals of gender are presumptively taken as authoritative (2009, 110-12). The political conflict, at any rate, is framed in terms of competing cultural formations where the dominant one possesses institutional power and the capacity to enforce a way of life and way of seeing the world, regardless of the personal costs to the trans people involved and regardless of subcultural socially practices which help give their lives meaning (2009, 115; 2012, 243; 2013, 53-54; 2014, 388-90). (One notable absence, in this view, is any account of how it is that trans people are motivated to transition and to occupy such trans cultural spaces in the first place. That is, there is no account of underlying gender dysphoria).