 What is known about donor motivation … is that it is multifaceted. People make decisions for a range of reasons, and competent adults are capable of assessing the relative benefits, burdens and likely impact of a range of options available to them. An incentive to donate does not necessarily mean people will do so purely because of that incentive. Indeed, the literature suggests that both donors and sharers have mixed motives for donating. (HFEA 2011: section 2, 4.4 [p. 8])