**Question:** All of the following statements regarding vas deferens are true except:

A. Vas deferens transport sperm from epididymis to ejaculatory ducts during ejaculation
B. Vas deferens have smooth muscle fibers that contract during ejaculation
C. Vas deferens are present in females
D. Vas deferens transmit motor neurons to control their contractions

**Core Concept:** Vas deferens are a part of the male reproductive system, responsible for transporting sperm from the epididymis to the ejaculatory ducts during ejaculation. They also contain smooth muscle fibers that contract during ejaculation. These smooth muscle fibers are under autonomic nervous system control, not under direct motor neuron transmission.

**Why the Correct Answer is Right:** Option D is incorrect because vas deferens do not transmit motor neurons to control their contractions. Instead, they are under autonomic nervous system control, specifically, the sympathetic division. This division stimulates the smooth muscle fibers in the vas deferens to contract during ejaculation, allowing sperm to be transported to the ejaculatory ducts.

**Why Each Wrong Option is Incorrect:**

A. While vas deferens do transport sperm, option C is incorrect because they are exclusively present in males, not females. Females have the oviducts for sperm transport and fertilization.

B. Although smooth muscle fibers do exist in vas deferens, option B is incorrect because these smooth muscle fibers are controlled by the autonomic nervous system, not by direct motor neuron transmission. The sympathetic division of the autonomic nervous system triggers the contractions during ejaculation.

**Clinical Pearl:** Understanding the role of vas deferens in sperm transport and the autonomic nervous system control of their contractions is crucial for understanding male fertility and male reproductive physiology.