Mothers (or mum/mom/mam(s)) are women who inhabit or perform the role of bearing some relation to their children, who may or may not be their biological offspring. Thus, dependent on the context, women can be considered mothers by virtue of having given birth, by raising their child(ren), supplying their ovum for fertilization, or some combination thereof. Such conditions provide a way of delineating the concept of motherhood, or the state of being a mother. Women who meet the third and first categories usually fall under the terms 'birth mother' or 'biological mother', regardless of whether the individual in question goes on to parent their child. Accordingly, a woman who meets only the second condition may be considered an adoptive mother, and those who meet only the third a surrogacy mother. The above concepts defining the role of mother are neither exhaustive, nor universal as any definition of 'mother' may differ based on how social, cultural, and religious roles are defined. The parallel conditions and terms for males: those who are (typically biologically) fathers do not, by definition, take up the role of fatherhood. It should also be noted that mother and fatherhood are not limited to those who are or have parented. Women who are pregnant may be referred to as expectant mothers or mothers-to-be, though such applications tend to be less readily applied to (biological) fathers or adoptive parents.