Consider the following hormones and their role in the workings of the endocrine system: Where the hormone is produced. Hormone(s) secreted. Hormone function. Adrenal glands. Aldosterone. Regulates salt, water balance, and blood pressure.
Sometimes there are tissue-specific mutations that control formation of certain tissues and/or organs. For instance, if mutation affects skin then the skin would be wrinkly/ugly but organism would still develop.
Although the genes for producing milk are carried by both males and females, only lactating females express these genes. The presence of drugs or chemicals in an organism's environment can also influence gene expression in the organism. Cyclops fish are a dramatic example of the way in which an environmental chemical can affect development.