Breasts are a secondary sexual characteristic, while the vagina is part of the reproductive and sexual anatomy. Both can be influenced by hormones, but that does not mean that their physical characteristics provide a reliable measurement of each other.
Human anatomy is more complicated than that.
The same principle applies to other body parts.
Someone’s height does not tell you the exact size of their hands.
The size of someone’s feet does not reliably reveal the size of their ears.
And breast size does not reveal vaginal anatomy.
There may be statistical relationships between some physical characteristics in certain populations, but a statistical association is not the same thing as a reliable prediction about an individual.
That distinction is especially important when discussing intimate anatomy.
People are naturally curious about the human body, and curiosity itself is not a problem. The problem arises when myths are presented as scientific facts.
