There's Something in my Milk...

Prenatal hormones play a significant role in the sexual development of fetuses. In utero, or during pre-birth development in a uterus, fetuses receive a concoction of different developmental hormones that help them develop. When a mother is pregnant with a males, she produces significantly more of the male sex hormone, testosterone, than if she were pregnant with a female (Wolf et al, 2002). Any deviation away from the normal balance of in utero hormones can cause developmental defects.

Below is a brief video explaining how testosterone, a sex hormone, functions in the body.

In her Dr. Lise Eliot's book, Pink Brain, Blue Brain: How Small Differences Grow Into Troublesome Gaps - and What We Can Do About It, Eliot stresses the immediacy of gender assignment in the womb. Upon the moment of conception, "a baby's sex is decided...and differences in the brain a mind [take] root before birth (Eliot, p. 20). Sexual differentiation doesn't occur until about halfway through the first trimester, but gender assignment precedes
development.

During and after the pregnancy, most couples are highly concerned with the particulars of their newborn(s): Sex, gender, health, nutrition, characteristics, etc. (Eliot, p. 19). After birth, the mother's role was believed to transition from hormonal supplementation to nutrition. Newborns are reliant on some form of breast milk for nutrition. Modern medicine has provided artificial methods of nutrition to help mothers avoid the baby's demands to stop everything, undress, and feed. Until recently, the mother's direct hormonal role in nutritional supplements was thought to stop after childbirth.

Prof Kate Hinde, Harvard University

Recent studies emerging from Professor Kate Hinde at Harvard University have implied the importance of natural breastfeeding ("Moms' Breast Milk"..., 2014). Natural breast milk contains a specialized combination of sex-specialized fats and proteins often not present in store-bought breast milk.  Natural breast milk has a different combination of these hormones, fats, and proteins based on the sex of the child. Hinde found that rhesus monkey "mothers produce milk with 35% more fat and protein for male babies, and even richer milk when the male was first born" (Baby Boys and Girls..., 2014). For female newborns, mothers  produced milk with less fatty acids and with more Calcium, believed to promote bone growth. The results of Hilde's research have shown that the body creates a specialized concoction of hormones for newborn babies. The implications of this study show that artificial breast milk is not as suitable for newborns as it was believed to be.

The American Association of Pediatrics recommends natural breast milk as the primary form of nutrition for newborns ("Breastfeeding...", 2014). Yet, where does this leave mothers incapable of producing breast milk? While natural breast milk is preferable, formula is still considered an acceptable alternative ("Formula...", 2012). Researchers, like the Hinde, are uncovering the subtleties behind human growth and development. As a result, manufacturers can begin to create healthier substitutes to breast milk.

Research may provide more accurate recipes for artificial breast milk, but for the time being it is safe to assume that natural breast milk is safer than artificial formula.

1. "Breastfeeding and the Use of Human Milk." Breastfeeding and the Use of Human Milk. N.p., n.d. Web. 23 Feb. 2014.
2. Cynthia J Wolf, et al. "Effects of Prenatal Testosterone Propionate on the Sexual Development of Male and Female Rats: A Dose-Response Study". 
3. Eliot, Lise. Pink Brain, Blue Brain: How Small Differences Grow into Troublesome Gaps--and What We Can Do about It. Boston: Houghton Mifflin Harcourt, 2009. Print."Formula Feeding FAQs: Getting Started." KidsHealth - the Web's Most Visited Site about Children's Health. Ed. Joseph DiSanto. The Nemours Foundation, 01 Jan. 2012. Web. 23 Feb. 2014."Moms' Breast Milk Differs Depending on Whether Baby Is a Boy or Girl." NY Daily News. N.p., n.d. Web. 23 Feb. 2014.
4. Sample, Ian. "Baby Boys and Girls Receive Different Nutrients in Breast Milk." Theguardian.com. Guardian News and Media, 14 Feb. 2014. Web. 23 Feb. 2014.
5. Toxilogical Sciences. Volume 65 (2002): 71-86. Web. 18 Feb 2013