What is the ratio of women to men in the world?

Approximately 1.1 males to females (2009).

According to the CIA World Factbook, as of 2009 there are 1.1 males to females which works out to about 50.25% males, 49.75% females given the total population of world being approximately 6,790,062,216.

Source:https://www.cia.gov/library/publications/the-world-factbook/geos/xx.htm