 This suggests that, in relation to solidarity, there is no categorical difference between payment and benefits-in-kind. While some egg sharers may be motivated mainly by feelings of solidarity, others may be more interested simply in saving money. Conversely, while some paid donors would be ‘in it just for the money’, others (perhaps those whose close friends or relatives have fertility problems, or who have experienced health problems of their own) could be moved to donate because of feelings of solidarity (the fact that they are financially rewarded notwithstanding). As such, it is by no means obvious that all egg sharers are motivated by feelings of solidarity, or that all paid donors would fail to have this feeling. Indeed, it is by no means obvious even that most egg sharers are motivated by feelings of solidarity and there is empirical evidence suggesting that the number of sharers significantly decreases when state funded treatment is made widely available (Pennings 2009).