The phrase 'their deficiency' is correct and completely usable in written English.
You can use it when referring to something that someone or some group does not have enough of, such as knowledge, skills, or abilities. For example, "My students are struggling with the material due to their deficiency in math skills."
The truly hairless can make up for their deficiency by doubling up on flair.
Worse, they attempt to compensate for their deficiency of funny by playing the dramedy card.
And even then, after the baby is born the surrogate can back out even if the child is not genetically hers.In the book of Genesis three women sent their husbands to their maidservants to remedy their deficiency in producing sonsSome American states ban surrogacy outright.
Their deficiency may cause a number of diseases.
It was the suffering of early explorers and sailors that motivated the first studies of vitamins and their deficiency diseases.
Their deficiency may cause certain diseases such as, gastrointestinal insufficiencies, inadequacy of proteins, inflammatory responses, detoxification impairments, cardiovascular disease, neurological dysfunction, and inborn errors of metabolism etc.
In turn, it is found that this coordinating contract is profitable and proper for items which the possibility of their deficiency is higher than the others.
There is reason to doubt that the compresence of opposites or the mere complexity of particulars is responsible for their deficiency (but see Fine 1993, esp. Ch. 4).
Such a drastic measure, however, would only be taken if a noncomplying institution failed to establish an ethics training program after being notified of their deficiency by ORI.
Their functions are understood largely by their deficiency diseases so we're not exactly sure of precisely what they all do or how they interact.
The metals Cu, Fe, Ni, Zn, and other trace elements are important for proper functioning of biological systems, and their deficiency, or excess, could lead to a number of disorders (Chopra et al. 2009).
