[6] The most extensive study to date, a 1981 survey of nearly 20,000 French males aged 17 to 26,[7] served to disprove many commonly held beliefs about the disorder.

In one quarter of cases sun exposure seems to have played a role, a number apparently lower than that expected by researchers.

Also surprising to researchers was the low incidence (32%) of Becker's nevi above the nipples, for it had generally been believed that the upper chest and shoulder area was the predominant site of occurrence.

As this was apparently the first documented co-occurrence of the two diseases, there is so far no evidence of higher malignancy rates in Becker's nevi versus normal skin.

Nonetheless, as with any abnormal skin growth, the nevus should be monitored regularly and any sudden changes in appearance brought to the attention of one's doctor.