The phrase "age pair" is correct and usable in written English.
It can be used in contexts where you are discussing two individuals or entities that are of similar or specific ages, often in studies or comparisons.
Example: "In the study, we focused on an age pair of 25-year-olds to analyze their health outcomes."
Alternatives: "age group" or "age cohort".
Within the social group or pack there is a complex dominance hierarchy based on age, pair-bonds, physical condition, and sexual state.
To review donor-egg assisted reproductive technology (ART) activity using young fertile donors (<37 years of age) paired with multiple recipients.
At 24 months of age, pairs of rats competed against each other for exclusive access to chocolate rewards.
To test whether the increases in core body temperature and activity might be due to greater food intake, 3xTgAD mice were food restricted to the average ad-libitum amount eaten by Non-Tg control mice at 10 months of age (pair-feeding paradigm).
There was a 41% decrease in epileptiform FFT power at this age (paired t‐test, P = 0.009; n = 6; Figs. 5A‐D, 6A; Table 2).
It was estimated that with a response rate of 60 to 70%, between 360 and 430 mother-child (up to four years of age) pairs would be recruited into this study, in addition to 100 women who were currently pregnant.
In a sample of 563 mother child (2 11 years of age) pairs, mothers with higher BMI levels were reported to have a lower level of control on their children's diet than mothers with normal BMI levels.
A couple of weeks ago, The Times's Jim Yardley reported from China that the world's last known female Yangtze giant soft-shell turtle was living in one Chinese zoo, while the planet's only undisputed, known giant soft-shell male turtle was living in another — and together this aging pair were the last hope of saving a species believed to be the largest freshwater turtles in the world.
