Skip to main content
Move the World.
sperm and pregnancy

Lead Image © Crevis / Adobe Stock

New research suggests that sperm play a bigger role in pregnancy than previously believed, not only fertilizing the egg, but also "persuading" the female body to accept it.

Revisiting sex ed: Human reproduction typically starts with sperm traveling via seminal fluid to an egg and fertilizing it. That creates a zygote, which can then attach to the wall of the uterus and begin the process of developing into a baby.

Implantation isn't a given, though. The woman's immune system may reject the fertilized egg as something "foreign" and prevent her from becoming pregnant.

Persuasive swimmers: Past research has shown that seminal fluid contains proteins that dampen this immune response, encouraging the woman's body to accept the zygote and the pregnancy.

Now, researchers at the University of Adelaide have discovered that sperm send their own signals designed to persuade the woman's body.

"This overturns our current understanding of what sperm are capable of," project leader Sarah Robertson said in a press release. "They are not just carriers of genetic material, but also agents for convincing the female to invest reproductive resources with that male."

The study: For a new study, female mice were mated with males who produced sperm and males who'd been vasectomized (meaning they produced seminal fluid without sperm).

Based on changes in the expression of different genes in the females' uteruses, the researchers determined that the sperm-producing mice prompted a stronger immune tolerance in their mates than the vasectomized rodents.

By introducing male sperm to female cells in the lab, the researchers were able to confirm that the sperm was directly responsible for the changes.

"This overturns our current understanding of what sperm are capable of."

Sarah Robertson

Why it matters: Infertility is a common issue, affecting tens of millions of couples across the globe, and problems such as recurrent miscarriage, preeclampsia, and stillbirth have all been linked to the female immune response during reproduction.

Now that we know that sperm can affect that immune response, researchers may be able to identify new ways to treat infertility — potentially helping some couples conceive and give birth to healthy babies.

We'd love to hear from you! If you have a comment about this article or if you have a tip for a future Freethink story, please email us at [email protected].

Up Next

Artificial Intelligence
AI That Predicts Pregnancy Complication Could Save Lives
Placenta Exam
Artificial Intelligence
AI That Predicts Pregnancy Complication Could Save Lives
By predicting future preeclampsia risk, the AI might save the lives of mothers and their babies.

By predicting future preeclampsia risk, the AI might save the lives of mothers and their babies.

Fertility
How GMO Zebrafish Could Inspire New Infertility Treatments
zebrafish  Infertility Treatments
Fertility
How GMO Zebrafish Could Inspire New Infertility Treatments
By genetically modifying zebrafish, researchers have discovered a sex hormone that could lead to future infertility treatments for humans.

By genetically modifying zebrafish, researchers have discovered a sex hormone that could lead to future infertility treatments for humans.

Dispatches
The Cause (and Possible Cure) for Most Infertility
The Cause (and Possible Cure) for Most Infertility
Dispatches
The Cause (and Possible Cure) for Most Infertility
Fertility medicine may be on the edge of a breakthrough.

Fertility medicine may be on the edge of a breakthrough.

Future of Fertility
For Childhood Cancer Survivors, Adult Fertility Isn’t a Given
For Childhood Cancer Survivors, Adult Fertility Isn’t a Given
Future of Fertility
For Childhood Cancer Survivors, Adult Fertility Isn’t a Given
Experimental procedures offer beta solutions for girls, and more time to figure it out for boys.
By Julia Sklar

Experimental procedures offer beta solutions for girls, and more time to figure it out for boys.

The Future Explored
Can a Lab-Grown Uterus Treat Infertility?
bioengineered uterus
The Future Explored
Can a Lab-Grown Uterus Treat Infertility?
A bioengineered uterus could open up treatment options for women facing infertility.

A bioengineered uterus could open up treatment options for women facing infertility.

Future of Fertility
Breaking the Taboo of Male Infertility
Breaking the Taboo of Male Infertility
Future of Fertility
Breaking the Taboo of Male Infertility
Male infertility contributes to up to half of infertility cases. Why is it so hard to talk about?

Male infertility contributes to up to half of infertility cases. Why is it so hard to talk about?

Fertility
Cancer Survivor Gives Birth Thanks to a New Fertility Procedure
Cancer Survivor Gives Birth Thanks to a New Fertility Procedure
Fertility
Cancer Survivor Gives Birth Thanks to a New Fertility Procedure
A French cancer survivor is the first person to give birth via a fertility treatment that involves freezing and thawing eggs that underwent in vitro maturation.

A French cancer survivor is the first person to give birth via a fertility treatment that involves freezing and thawing eggs that underwent in vitro maturation.

Future of Medicine
THC Could Help Women With Endometriosis
thc for endometriosis
Future of Medicine
THC Could Help Women With Endometriosis
Hundreds of thousands of women suffer with endometriosis, a disorder that causes painful tissue growth outside of the uterus. Pending clinical trials around THC may finally spell relief.
By Sarah Wells

Hundreds of thousands of women suffer with endometriosis, a disorder that causes painful tissue growth outside of the uterus. Pending clinical trials around THC may finally spell relief.