Have Contraceptives created Weaker Humans?

And does it explain infidelity?

Photo by Reproductive Health Supplies Coalition on Unsplash

Introduction

The Major Histocompatibility Complex (MHC) is a part of DNA that codes proteins essential for the adaptive immune system. Human immune systems consists of the innate immune system, which is pre-programmed to deal with a broad range of pathogens and the adaptive immune system. As you may have learnt during the pandemic, the adaptive immune system works by creating an immune response to specific pathogens, e.g. using antibodies.

It is a no-brainer that our immune systems should be as strong as possible. Furthermore, they should be as flexible as possible, in order to react to any new potentially harmful pathogens.

One theory on how our immune systems remain ‘ahead of the game’ is that sexual reproduction “allows animals (including humans) to react rapidly to a continuously changing environmental selection pressure such as coevolving parasites”.

Animal studies have revealed that animals choose a mate that are MHC-dissimilar to themselves. So much so that females that end up with partners who are MHC-similar to themselves, seek to improve offspring quality through extra-pair partnerships (translation - they get pregnant with another bloke).

Birth Control Studies