It’s undeniable that breast milk is downright incredible. From the way it adapts to meet your baby’s needs at different times to its immune-boosting qualities, breast milk deserves all the applause.

“It is incredible that your body can provide such a magical substance for your baby,” says Diana Spalding, CNM, a Motherly advisor and midwife. “It’s just more proof that we know how to mother our children intuitively.” Here are more ways the breast milk science continues to amaze us.

Learn more about the science behind why breast milk is magic.

1. Mothers’ breast milk varies based on the child’s sex

Studies have shown that the breast milk mamas produce varies in significant ways based on whether they are feeding a boy or girl. Specifically, the milk produced for female offspring (across a number of different mammal groups, including humans) tends to be lower in fat and protein than that created for males.

But making this even more remarkable are the adaptations in milk for children’s sexes in different cultures: As a 2012 study published in Nature found, impoverished mothers in Kenya produced fattier, higher-quality milk for daughters versus sons—which led researchers to hypothesize this is because girls stand a better chance at raising their family’s profile through beneficial marriages.

Related: Breastfeeding helped me love and appreciate my body—finally

2. The composition of breast milk changes as baby ages

As any mom who has witnessed the first days of colostrum give way to bags and bags of expressed milk can attest, babies’ nutritional needs change as they grow—and breast milk keeps up. And these changes to breast milk continue as babies age: According to a study published in the journal Pediatrics, the fat and energy contents in milk expressed from moms who have been lactating for more than one year were “significantly increased” than the fat and energy contents in milk from moms breastfeeding younger babies.

Related: Should you pump colostrum during pregnancy?

3. Breast milk adapts when baby’s sick to provide stronger antibodies

When a nursing baby comes down with a cold, research shows the numbers of leukocytes in the mother’s breast milk spikes. Even more incredible to think about is the theory about how this information is communicated from baby to mama: Although research is limited, there are some strong scientific suggestions that backwash from baby’s mouth through mother’s nipple can carry signals that indicate the need for more antibodies.

Related: Covid vaccine antibodies found in breast milk

4. Breastfeeding reduces rates of certain ailments

Studies show breastfed infants grow up to experience lower rates of asthma and allergies, and the reason why may be because the short-chain fatty acids found in breast milk are uniquely able to line infants’ colons and lead to stronger immune responses. And that’s not to mention that a study suggested the human proteins found in breast milk may aid in battling cancer.

Related: An element in breast milk may help prevent certain cancers

mom holding newborn baby while drinking coffee

Motherly Classes


The 4th Trimester: A doula's guide to everything you need to know class

Welcoming a baby is an overwhelming joy… and, honestly, also an overwhelming experience! That’s why this class is here for YOU, covering postpartum care, lactation, normal newborn behavior — and all the emotions that come with the fourth trimester.

mom breastfeeding a baby using a boppy

Motherly Classes


Ready, Set, Latch!

Welcome to the best breastfeeding class for new and expectant parents! Rebecca Ellison’s essential research-based, expert-taught, comprehensive class is full of realistic and practical tips given in a non-judgmental approach

5. Human breast milk is especially designed for our brainy babies

Although all mammal mamas produce oligosaccharides in their breast milk, human mothers are super oligosaccharides producers—with some 200+ varieties of human milk oligosaccharides (HMOs). The amazing part? Our babies can’t even digest these simple sugars.

But while they can’t directly digest oligosaccharides, research that has been in development for years shows the HMOs promote productivity in infants’ guts and, in turn, helps them digest protein and other forms of energy more effectively. Following that reasoning, evolutionary scientists believe humans are (totally subconsciously) investing the energy into HMO production to give our brainy babies a bigger boost.

Related: There’s an antimicrobial compound in breast milk that could help formula-fed babies, too

6. Breast milk during nighttime nursing sessions promotes infant sleep

Good news for any mama ready to get her baby back to sleep ASAP after a nighttime feed: Breast milk produced in the twilight hours has higher levels of sleep-promoting nucleotides than milk expressed during the day. This finding led researchers to suggest pumping moms offer milk expressed during certain times of the day to their babies at that same time of day—because the wonders of breast milk are really only just being revealed.

While breastfeeding may not be an easy journey, it sure is comforting to remember that not only are you helping your baby grow—but you’re also working some magic while doing it.