Featured Research

from universities, journals, and other organizations

Fathers wired to provide offspring care; Study confirms that testosterone drops steeply after baby arrives

Date:
September 13, 2011
Source:
Northwestern University
Summary:
A new study provides compelling evidence that human males are biologically wired to care for their offspring, conclusively showing for the first time that fatherhood lowers a man's testosterone levels. The effect is consistent with what is observed in many other species in which males help take care of dependent offspring.

Human males are biologically wired to care for their offspring, new research confirms.
Credit: Melissa Schalke / Fotolia

A new Northwestern University study provides compelling evidence that human males are biologically wired to care for their offspring, conclusively showing for the first time that fatherhood lowers a man's testosterone levels.

The effect is consistent with what is observed in many other species in which males help take care of dependent offspring. Testosterone boosts behaviors and other traits that help a male compete for a mate. After they succeed and become fathers, "mating-related" activities may conflict with the responsibilities of fatherhood, making it advantageous for the body to reduce production of the hormone.

"Humans are unusual among mammals in that our offspring are dependent upon older individuals for feeding and protection for more than a decade," said Christopher W. Kuzawa, co-author of the study and associate professor of anthropology in the Weinberg College of Arts and Sciences. He also is a faculty fellow at the Institute for Policy Research at Northwestern. "Raising human offspring is such an effort that it is cooperative by necessity, and our study shows that human fathers are biologically wired to help with the job."

Past studies showing that fathers tend to have lower testosterone levels were small and not conclusive regarding whether fatherhood diminished testosterone or whether men with low testosterone in the first place were more likely to become fathers. The new study takes a novel approach by following a large group of men who were not fathers and seeing whether their hormones changed after becoming fathers.

"It's not the case that men with lower testosterone are simply more likely to become fathers," said Lee Gettler, a doctoral candidate in anthropology at Northwestern and co-author of the study. "On the contrary, the men who started with high testosterone were more likely to become fathers, but once they did, their testosterone went down substantially. Our findings suggest that this is especially true for fathers who become the most involved with child care."

The new study's findings also suggest that fathers may experience an especially large, but temporary, decline in testosterone when they first bring home a newborn baby. "Fatherhood and the demands of having a newborn baby require many emotional, psychological and physical adjustments," Gettler said. "Our study indicates that a man's biology can change substantially to help meet those demands."

The authors also suggest that their findings may provide insight into one reason why single men often have poorer health than married men and fathers. "If fathers have lower testosterone levels, this might protect them against certain chronic diseases as they age," Kuzawa said.

The study followed a group of 624 males aged 21.5 to 26 years old for 4.5 years in the Philippines.

The study was published Sept. 12, 2011, in the Proceedings of the National Academy of Sciences.

The study's co-authors, along with Gettler and Kuzawa, are Thomas W. McDade, professor of anthropology and Institute for Policy Research faculty fellow, Northwestern University, and Alan Feranil, director, Office of Population Studies Foundation, University of San Carlos, Cebu City, Philippines. The research was funded by the National Science Foundation and the Wenner Gren Foundation.


Story Source:

The above story is based on materials provided by Northwestern University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Lee T. Gettler, Thomas W. Mcdade, Alan B. Feranil, Christopher W. Kuzawa. Longitudinal evidence that fatherhood decreases testosterone in human males. Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1105403108

Cite This Page:

Northwestern University. "Fathers wired to provide offspring care; Study confirms that testosterone drops steeply after baby arrives." ScienceDaily. ScienceDaily, 13 September 2011. <www.sciencedaily.com/releases/2011/09/110912152901.htm>.
Northwestern University. (2011, September 13). Fathers wired to provide offspring care; Study confirms that testosterone drops steeply after baby arrives. ScienceDaily. Retrieved August 27, 2014 from www.sciencedaily.com/releases/2011/09/110912152901.htm
Northwestern University. "Fathers wired to provide offspring care; Study confirms that testosterone drops steeply after baby arrives." ScienceDaily. www.sciencedaily.com/releases/2011/09/110912152901.htm (accessed August 27, 2014).

Share This




More Health & Medicine News

Wednesday, August 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Predicting Heart Transplant Rejection With a Blood Test

Predicting Heart Transplant Rejection With a Blood Test

Ivanhoe (Aug. 27, 2014) Now a new approach to rejection of donor organs could change the way doctors predict transplant rejection…without expensive, invasive procedures. Video provided by Ivanhoe
Powered by NewsLook.com
Better Braces That Vibrate

Better Braces That Vibrate

Ivanhoe (Aug. 27, 2014) The length of time you have to keep your braces on could be cut in half thanks to a new device that speeds up the process. Video provided by Ivanhoe
Powered by NewsLook.com
Smartphone App Tracks Your Heart Rate

Smartphone App Tracks Your Heart Rate

Ivanhoe (Aug. 27, 2014) A new app that can track your heart rate 24/7 is available for download in your app store and its convenience could save your life. Video provided by Ivanhoe
Powered by NewsLook.com
Stroke in Young Adults

Stroke in Young Adults

Ivanhoe (Aug. 27, 2014) A stroke can happen at any time and affect anyone regardless of age. This mother chose to give her son independence and continue to live a normal life after he had a stroke at 18 years old. Video provided by Ivanhoe
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins