No. The myth that trading boxer shorts for briefs can affect your ability to have an erection is really just a myth. Wear whatever type of undergarments you want without worrying about whether they’re affecting erection quality or your erectile health.
Relax! Your choice of underwear won’t affect your ability to have an erection.
How did the “tight underwear” myth get started?
Tight underwear has been associated with lower sperm count, but that’s an entirely different problem, despite the fact that it takes place in the same anatomical vicinity. Low sperm count is a leading cause of infertility, but that’s separate and apart from whether a man can have strong erections.
The association between tight underwear and low sperm count is related to the temperature of the testicles. To produce sperm that’s sufficiently healthy, and in sufficient quantities, the testicles must be slightly cooler than the core body temperature. That is why they’re located externally. Tight underwear, by putting the testicles closer to the body, can cause temperature to rise, so sperm quality and quantity can suffer.
There are two important things to bear in mind. One, it takes something like 10 weeks for sperm to be produced, so the tight underwear-low sperm count connection is a long-term process and not an overnight process. Two, wearing tight underwear in hopes of reducing sperm count as a half-hearted attempt at birth control won’t work and is a stupid thing to try.
But if tight underwear is bad for sperm production, why wouldn’t it be bad for erections too?
Tight underwear doesn’t affect your cardiac fitness, so it won’t cause erectile dysfunction.
The process that produces sperm is separate from the process that causes you to have an erection. Erectile health is closely related to cardiac health. Healthy production of sperm in large quantities depends in part on operating in an environment that is slightly cooler than the body’s core temperature. Hence, if the testicles aren’t cool enough, sperm count can suffer without there being any effect on erectile functioning.