I've known about this phenomenon for a long time, but this is the first I knew that it had a name with capital letters.
There are 105 boy babies for every 100 girl babies (at least I assume this based on the male to female ratio of ages 0 to 5 in the US Census).
The ratio of single (defined as separated or not married) men to single women in lower age brackets becomes even larger because of serial polygamy, which is the tendency of some older men to divorce and marry a lot younger.
Using the 2000 U.S. Census data, and looking only at respondents who claimed to be white, in the age bracket of 18-29, there are 119 single men for every 100 single women.
It doesn't get much better for men in their thirties. For white people aged 30-39, there are 117 single men for every 100 single women.
As we see, dating life is much harder for under-40-year-old men than it is for women.