 Insofar as our cultural conceptions affect our understandings of sex, feminists must be much more careful about sex classifications and rethink what sex amounts to (Stone 2007, chapter 1). More specifically, intersex people illustrate that sex traits associated with females and males need not always go together and that individuals can have some mixture of these traits. This suggests to Stone that sex is a cluster concept: it is sufficient to satisfy enough of the sex features that tend to cluster together in order to count as being of a particular sex. But, one need not satisfy all of those features or some arbitrarily chosen supposedly necessary sex feature, like chromosomes (Stone 2007, 44). This makes sex a matter of degree and sex classifications should take place on a spectrum: one can be more or less female/male but there is no sharp distinction between the two. Further, intersex people (along with trans people) are located at the centre of the sex spectrum and in many cases their sex will be indeterminate (Stone 2007).