## Core Concept
Estrogens are a class of steroid hormones that play a crucial role in the reproductive and sexual health of females, but they also have various effects on other tissues. The adverse effects of estrogens can be significant and impact multiple systems in the body. Understanding these effects is essential for managing patients on estrogen therapy.

## Why the Correct Answer is Right
The correct answer, **D.**, is associated with an effect that is not typically considered an adverse effect of estrogen. Estrogens are known to have several beneficial effects, particularly on bone density and the cardiovascular system, by influencing **lipid profiles** and promoting **vasodilation**.

## Why Each Wrong Option is Incorrect
- **Option A:** Estrogen can cause **thromboembolic events** due to its effect on coagulation factors and increasing the risk of venous thrombosis. This is a well-recognized adverse effect.
- **Option B:** Estrogen therapy is associated with an increased risk of **endometrial cancer** in women with an intact uterus, primarily due to unopposed estrogen stimulation on the endometrium. This risk can be mitigated with the addition of progestin in hormone replacement therapy (HRT) for women with a uterus.
- **Option C:** **Breast tenderness** or gynecomastia in men is another common side effect of estrogen therapy, resulting from the hormonal influence on breast tissue.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that the risk of **adverse effects** can be minimized by careful **selection of patients**, **monitoring**, and choosing the **appropriate type and dose of estrogen**. For example, the use of **combined estrogen and progestin therapy** in postmenopausal women helps mitigate some risks like endometrial cancer.

## Correct Answer: D.