It will be an even 20 for Michelle and Jim Bob Duggar, who announced Tuesday that they're expecting their 20th child. The Duggars, stars of their own TLC show, are a source of fascination for some people, since super-sized families aren't the norm the way they were about a century ago.
Michelle Duggar, you'll recall, didn't have such an easy time around with her last pregnancy in 2009. Daughter Josie was delivered early when it was discovered that Michelle had preeclampsia and gall bladder problems (Josie is now doing fine). Preeclampsia usually occurs later on in pregnancy and is characterized by high blood pressure and high protein levels in the urine. It can cause serious complications for the mother (stroke, seizure) and baby (insufficient blood flow to the placenta).
Even if Michelle has a trouble-free pregnancy, there are certain health risks--and benefits--linked with large families. One 2007 study in PLoS Medicine found an association between being a younger member of a large family and having a greater risk of stomach cancer.
Researchers looked at data on more than 9,935 Japanese American men who were followed for 28 years. They discovered that men who carried specific H. pylori bacteria strains and came from families with seven-plus siblings were more than twice as likely to get stomach cancer than men who also had the bacteria and had up to three siblings. Younger siblings may be more vulnerable, the authors said, because their immune systems may be weaker when they're exposed to the bacteria from their siblings.