General info on paired donation: Paired Donation

What may not be evident at first glance is that paired kidney
transplants are exceedingly difficult to accomplish. It's very hard to
match suitable pairs, and to have any reasonable chance of paired
kidney donation making any sort of impact on the number of transplants
performed overall, the system needs to have access to a very large
pool of potential recipients and donor pairs who are willing to
participate.

Canada has a much smaller population to draw from compared to the
U.S., plus, that smaller population is already divided up into smaller
provincial ones when it comes to transplant waiting lists. There is no
national transplant list in Canada as there is in the U.S., and so by
having a national registry for paired donation, it is hoped that this
will provide the larger pool of potential donor/recipient pairs needed.

Paired donation is when you have two people who need a kidney, and
each has a willing and qualified live donor who isn't a match for them
but might be for another pair. Once you get past that point of finding
the paired matches, then you still have to pass all the other matching
and health-related matters, and in addition, both pairs must be
available for the transplant operation at the same time.

In the US, you already have a national registry. I don't know how it
relates to paired donation at the moment, but another plus in your
favour is the much larger population to draw matching pairs from.

While I agree with the benefits of paired kidney donation, I can see a
few problems as well, such as the fact that it inevitably favours
certain blood types for pairs. I can also see it causing family
problems as from now on, spouses and other qualified family members
will be under pressure to do this if they are not the right blood
type. Until now, you weren't the right blood type, that was the end of
it.