As we've noted more than once around here the only country that doesn't have people dying while waiting for a kidney is the only country that pays live donors for a kidney - Iran. But, as we're also continually told, we should never sully matters concerning body parts with mere money.
Thus gamete donors are not compensated and we import sperm from Denmark, people do die waiting for a kidney or liver and blood, well, blood's interesting. For the system of voluntary donation does largely cover British needs. But plasma doesn't:
The global demand for plasma is growing, and cannot be met through altruistic donations alone. Global plasma exports were worth $126bn in 2016—more than exports of aeroplanes.
…Only countries that pay for plasma are self-sufficient in it.
The UK is one of those places which imports plasma. And we're importing it from paid donors in the US. The moral point has already, therefore, been trumped. We are paying donors for their plasma. But still there is the insistence that we must not ever pay for anybody part - even when we already do.
Our own view is that efficiency trumps the ethical concerns of some. After all, those who object to the financialisation of such medicine can always register their protest by dying without it.