Your babys sex organs and urinary system begin to form very early in pregnancy.

Here’s how they develop.

Was this article helpful?

pregnant woman holding ultrasound

We believe you should always know the source of the information you’re seeing.

Learn more about oureditorial and medical review policies.

Fetal Development: The 1st Trimester.

Article image

2022.https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/prenatal-care/art-20045302Opens a new window[Accessed June 2022]

Embryology, Sexual Development.

Chapter 3, Sex Begins in the Womb.

2001.https://www.ncbi.nlm.nih.gov/books/NBK222286/Opens a new window[Accessed June 2022]

Louisiana Department of Health.

Article image

Stage of Fetal Development: First Trimester.

Undated.https://ldh.la.gov/page/986Opens a new window[Accessed June 2022]

NHS.

You and your baby at 13 weeks pregnant.

close-up of fetus resting (animation)

2021.https://www.nhs.uk/pregnancy/week-by-week/13-to-27/13-weeks/Opens a new window[Accessed June 2022]

Nova Online.

2001.https://www.pbs.org/wgbh/nova/baby/fert_text.htmlOpens a new window[Accessed June 2022]

NHS.

2021https://www.nhs.uk/pregnancy/your-pregnancy-care/20-week-scan/Opens a new window[Accessed June 2022]

Seminars in fetal and neonatal medicine.

go to video page

Renal development in the fetus and premature infant.

2017.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5387761/Opens a new window[Accessed June 2022]

NIH.

Non-Invasive Prenatal Testing (NIPT) for Fetal Sex Determination.

colorful dots on a white background

2016.https://pubmed.ncbi.nlm.nih.gov/29553638/Opens a new window[Accessed June 2022]

Mount Sinai.

2021.https://www.mountsinai.org/health-library/tests/amniocentesisOpens a new window[Accessed June 2022]

Cleveland Clinic.

Chorionic Villus Sampling for Prenatal Diagnosis.

baby holding mother’s finger with her tiny hand

2021https://my.clevelandclinic.org/health/diagnostics/4028-chorionic-villus-sampling-for-prenatal-diagnosisOpens a new window[Accessed June 2022]

Seminars in Fetal and Neonatal Medicine.

Renal development in the fetus and premature infant.

  1. https://www.sfnmjournal.com/article/S1744-165X(17)30001-X/fulltext [Accessed June 2022]

MedlinePlus.

woman and partner looking at ultrasound photos

2021.https://medlineplus.gov/ency/article/002398.htmOpens a new window[Accessed June 2022]

University of Michigan Medical School.

Anatomy, Urinary System.

2007.https://pubmed.ncbi.nlm.nih.gov/17999044/Opens a new window[Accessed June 2022]

March of Dimes.

phone with BabyCenter app

2020.https://www.marchofdimes.org/pregnancy/amniotic-fluid.aspxOpens a new window[Accessed June 2022]

ACOG.

She lives in Colorado with her husband and young son and daughter.

Maggie Getz