While we're on the topic of vices, let's talk about caffeine. Researchers have previously suggested that women with fertility problems won't benefit from drinking lots of coffee.
Apparently those who drink more than four cups of the black stuff a day can reduce their chances of falling pregnant by about 26%.
However, the study did only look at women with fertility problems, so most women shouldn't feel guilty about having a morning cup of coffee. But, you should avoid drinking lots of caffeine.
Oh, and a final vice...drugs! Needless to say - drugs are bad. So any recreational drugs you may dabble with need to become a thing of the past - and pronto.