News | Published June 14, 2012

Ask the pediatrician: insect repellent, soy formula

Hi Dr. Collison,

What are your recommendations for using mosquito/tick repellent on children? Are there brands more suitable for children 10 and under? Are there other safe environmental solutions/products used to reduce the ticks and mosquitoes in the backyard?

Insect repellents can do a good job in keeping biting insects off but do not prevent stinging insects from making contact with you or your child. There are many natural insect repellents that are generally safe but less effective than those that contain DEET. The American Academy of Pediatrics (AAP) recommends using insect repellents with between 10 and 30% DEET for the maximum protection for children. Using more than 30% DEET is not recommended and doesn't seem to protect any better than 30%, and is more likely to cause skin reactions.

In regards to pesticides for the yard, I am not an expert with this and recommend that you consult a pesticide specialist before treating the area that your kids play in.

Some people try alternate methods to repel ticks and mosquitoes - which is fine if they are effective. The following methods have been shown not to work effectively:

  • Wristbands soaked in chemical repellents
  • Garlic or vitamin B1 taken by mouth
  • Ultrasonic devices that give off sound waves designed to keep insects away
  • Bird or bat houses to attract natural bug predators
  • Backyard bug zappers (this may actually attract insects to your yard).

Tips for Using Repellents Safely

Once you've found a product that works for you and your family, here are some bug repellent safety tips:


  • Read the label and follow all directions and precautions.
  • Only apply insect repellents on the outside of your child's clothing and on exposed skin.
  • Spray repellents in open areas to avoid breathing them in.
  • Use just enough repellent to cover your child's clothing and exposed skin. Using more doesn't make the repellent more effective. Avoid reapplying unless necessary.
  • Assist young children when applying insect repellents on their own. Older children also should be supervised when using these products.
  • Wash your children's skin with soap and water to remove any repellent when they return indoors, and wash their clothing before they wear it again.


  • Never apply insect repellent to children younger than 2 months.
  • Repellents should not be sprayed directly onto your child's face. Instead, spray a little on your hands first and then rub it on your child's face. Avoid the eyes and mouth.
  • Insect repellents should not be applied on cuts, wounds, or irritated skin.
  • Don't buy products that combine DEET with sunscreen. The DEET may make the sun protection factor (SPF) less effective. These products can overexpose your child to DEET because the sunscreen needs to be reapplied often.


Dr. Collison,

I was wondering if any research has been done to see if there is any correlation to soy formula and early puberty. My daughter drank soy formula and I am wondering if this will have an impact on her.

Soy formulas are readily available in the United States and used by approximately 12% of infants during the first year of life. Soy formula does contain some compounds known as phytoestrogens and isoflavones. These compounds are similar in structure to human estrogen and have been questioned as having negative impacts on sexual development, neurobehavioral development, immune function and thyroid function. There are also potentially protective effects from these compounds with heart disease and cancers of the breast, uterus and prostrate.

In reference to your question about premature puberty, there is no direct evidence that the presence of these chemicals in soy formula causes premature puberty. In general terms, the age of puberty has gotten younger over the past 50 years while the use of soy formula has decreased over the same time period. If soy was to blame, it would make sense for the pubertal age to get older or for our population eating less soy formula over the same time frame.

There are studies in animals that show some estrogen effects on soy-fed mice, but these have not been shown to consistently occur in human populations. Studies continue but at this point there is no conclusive evidence that ingesting soy is harmful for infants, children or adults.

Given the long experience with soy and the lack of consensus from the research on any bad effects from it, I suggest that you don't worry that your use of soy will cause any specific problems with your daughter's pubertal development. Attempting to live with them while they are going through their pubertal changes is another matter. :)