Which factor must not be included when calculating whether a borrower's debts exceed 50% of their gross income?

When determining whether a borrower's debts exceed 50% of their gross income, the focus is on financial obligations in relation to income. Monthly debts represent the borrower's existing obligations, and expected income is critical in assessing their ability to manage those debts. Employment status can affect income stability and future earning potential, indirectly influencing debt repayment capacity.

However, a borrower's age does not directly impact the calculation of debts in relation to income. Age may be relevant in a broader context, such as qualifying for certain loan products or understanding the borrower's life stage, but it does not play a role in the mathematical equation of calculating the debt-to-income ratio. Thus, it is appropriate to exclude age from the calculation, making it the correct choice in this question.