Biology of Humans 6th Edition by Judith Goodenough,Betty McGuire

Exercise 6

In the article "Prenatal Hormones in First-Time Expectant Parents: Longitudinal Changes and Within-Couple Correlations," Robin S. Edelstein and five colleagues at the University of Michigan describe how they monitored levels of four key hormones-testosterone, cortisol, estradiol, and progesterone-in 29 expectant couples. They measured hormone levels in saliva samples collected from expectant mothers and fathers at weeks 12, 20, 28, and 36 of pregnancy. The researchers found that mothers-to-be showed large increases in levels of all four hormones. Fathers-to-be, on the other hand, showed small but significant declines in testosterone and estradiol, and no changes in levels of cortisol and progesterone. The article was first published online December 15, 2014. The citation for the online article is: R. S. Edelstein, B. M. Wardecker, W. J. Chopik, A. C. Moors, E. L. Shipman, and N. J. Lin, "Prenatal hormones in first-time expectant parents: Longitudinal changes and within-couple correlations," American Journal of Human Biology. [2014]. DOI: 10.1002/ajhb.22670. When reporting on this research, the Daily Mail Online (Fiona Macrae, Daily Mail Science Correspondent, Published: 11:17 EST, 16 December 2014, and Updated: 22:23 EST, 16 December 2014) used the following headline: "Men Suffer Pregnancy Symptoms Too: Fluctuating Hormones Make Fathers-to-Be Less Aggressive and More Caring." The entire article by Fiona Macrae can be found at: www.dailymail.co.uk/health/article-2876240/Mensuffer- pregnancy-symptoms-Fluctuating-hormones-make-fathers aggressive- caring.html
Describe a key limitation of the study by Edelstein and colleagues. Does this limitation cause you to doubt their findings Explain your answer.