[cm2187]

A relative of mine who is a doctor mentioned to me that the opposite is a common problem when children volunteer to donate an organ to a parent. They must test for DNA compatibility which often yields bad surprises. Apparently it is gradual. The DNA of the first child almost always matches, the second a little less, the third is where the odds reduce significantly.

Granted that was in France...

[narag]

That's not the opposite, it's the same thing looking from a different place.

[JdeBP]

A different position is the primary meaning of "opposite". It does not necessarily mean "contrary".