In Reply Matas cites an article that provides the necessary definitions of the 3 categories of living kidney donation.1 Although he characterizes these as distinct, they actually overlap. Advanced donation, which first occurred in a kidney-paired donation when a donor needed to donate before their biologically incompatible recipient received a kidney from a nondirected donor, now occurs under a variety of circumstances. Voucher-based donations constitute a subgroup within the category of advanced donation.2 When originally developed, they were meant to accommodate someone who is chronologically incompatible with their prospective recipient whose need for a transplant might arise at a future time when the donor would no longer be able to provide an organ.3 When such a person becomes a donor, a voucher is created, which the patient in question can use to obtain a kidney (for example, at the end of a chain of paired donations) if that is ever needed.