"Teaching women to examine their breasts regularly has been shown not to reduce deaths from breast cancer and actually increases the chances of a benign biopsy result," claimed Margaret McCartney, a Glasgow-based general practitioner.
It is unfair to tell women that regular self examination would save their lives when it may simply incur anxiety and have the potential to harm, she explained.
The 'check 'em Tuesday' campaign is a weekly call for women to examine their breasts.
A non-profit organisation CoppaFeel, which is involved with The Sun's campaign, offers text message reminders to prompt women to do a regular self examination.
McCartney points out that this is just one aspect of a bigger move to promote untested 'breast awareness'.
For example, the charity Breakthrough Breast Cancer, which is not connected to The Sun's campaign, tells women to "touch, look, feel" regularly and advocates "knowing what your breasts look and feel like normally" as well as being able to name "the five signs of breast cancer".
According to McCartney, public health messages should be based on evidence and that their effects need to be proved to affect behaviour in a way that is helpful and not harmful.
"If we fail to critically evaluate campaigns on cancer, we create the appearance of doing something useful while potentially distracting from what might really help. In doing so, we potentially harm the very women we're purporting to help," she commented in a report published in British Medical Journal.