http://www.dailymail.co.uk/pages/live/articles/news/news.html?in_article_id=377839&in_page_id=1770 Reminds me of another piece of article I read in one Khuswant Singh's joke book. Here is it: Genetically its possible for a woman to bear twins fathered by two different fathers. This can happen when a woman has sexual intercourse with 2 men within a short interval. If the mother ovulates more than one egg and has more than one partner during her fertile period, one egg is fertilized with sperm from one partner, and the other egg from sperm of the second partner resulting in 2 different fathers for the same pair of twins. This rare phenomenon is known as the milkman effect. In case you are wondering why they have picked on the poor milk supplier let me tell you. In most of the western world milkmen deliver bottles in the morning after husbands have left for work and wives are still in their flimsy negligees. Many a wife has been tempted to offer her milkman a warm cup of tea in the kitchen followed by a session in a warmer bed. So this is where the milkman comes from. One classic case of "the milkman effect" was described in 1810 in the United States. A woman had both a white and a black lover, and she became pregnant and gave birth to twins, one white and the other mulatto. Interesting, isnt it?