Here's How Your Baby's Sex Influences The Composition Of Your Breast Milk

I've only ever given birth to boys, and they were supremely good eaters. They would both literally breastfeed until I had nothing left to feed them. When they were babies, I read about how breast milk can change based on each babies' nutritional needs. I knew that my breast milk contained exactly the nutrients they each specifically needed, but what I did not know was if there would be a difference between the milk I produced for them and what my body would make if I had a baby girl someday. Is breast milk different for boy and girl babies? Do they have different nutritional requirements that breast milk can meet?

To answer that question, I asked several lactation experts to weigh in. It is pretty commonly known that the benefits of breast milk can do amazing things for babies. Research shows that the nutrients in breast milk are unique to the needs of the baby being fed. The composition of a mom's milk changes when babies are sick, when they are growing, and even when they are feeding at night versus during the day, so it is really no surprise that the make-up of a mother's milk can also be different for boy babies and girl babies.

The Daily News reported in 2014 that researcher Katie Hinde, an evolutionary biologist at Harvard, said that her studies in a variety of mammals found that milk produced by mothers of baby boys contained more fat and and protein, while milk produced by mothers of baby girls contained higher levels of calcium. However, the jury is still out on exactly why this phenomenon occurs.

Rachael Kish, Certified Lactation Consultant and co-founder of Imalac, tells Romper that the nutritional value of the milk a mother produces is based on what each individual baby needs. "According to some research and findings, nursing mothers with boy infants are said to produce milk that is more nutrient dense. However, to my knowledge, breast milk is continuously changing based on the baby’s needs, regardless of their sex. As babies grow, the composition of breast milk will shift and can even vary from feeding to feeding. Breast milk also varies from mother to mother because of one's personal diet and flavor profiles, but typically not from baby to baby," she says.

Although there may be slight nutritional differences in the milk produced for boys versus girls, Kish says that there is no reason to tailor breast feeding practices to specific genders. "There is no difference in how you approach breastfeeding boys or girls. Approaches will vary based on the individual baby’s needs or mom’s schedule, but has nothing to do with the sex of your baby. They will have their own feeding habits, schedules, favorite positions, likes and dislikes that make them unique," she says.

In addition to the nutritional differences that breast milk produces for each baby, there are some societal differences that Tera Hamann, IBCLC, RN, BSN has noticed in her professional career helping nursing moms feed boys versus girls. "I think that in our country, breasts have been so specialized, that some moms are more hesitant to nurse boys, especially to term. World Health Organization recommends nursing until at least [age] 2. Their immune systems are not fully developed and nursing is beneficial to their immune system until 3 to 4 years of age. I have also seen/heard feedback from support people that were more uncomfortable with boy babies nursing to self-weaning," she tells Romper.

Hamann recommends that moms who needs support feeding either boys or girls turn to professionals for advice. "If a mom is struggling to nurse, seek out hands on help, preferably from an IBCLC," she says. "There are a lot of resources available — most hospitals, WIC, private practice lactation, as well as support groups like La Leche League."