The other major problem is the homes themselves. In terms of toxicity, the worst offenders here are: carpets and carpet backings, foam mattresses, paints, varnishes and items containing fire retardant chemicals. The fire retardant chemicals used in mattresses, for example, have been found to contribute to birth defects (see this EWG report for example). Basically, all of these household items can emit a steady flow of toxic, airborne chemicals. Homeowners unknowingly inhale these chemicals with every breath.
So how can you create a healthy home?
Here's the extremely short answer: Stop buying toxic household products, use natural cleaning products, remove carpeting and replace with wood floors or natural rugs, use low-VOC paints, and add indoor plants to your home for filtration purposes.
Want more information on this topic?
:: See this book for a general introduction: The Healthy Living Space: 70 Practical Ways to Detoxify the Body and Home.
See the News Target web site, which a good source of articles dealing with household toxicity issues.