  Insurance and annuity products covering several lives require the modelling
of the joint distribution of future lifetimes. In the interest of simplifying
calculations, it is common in practice to assume that the future lifetimes
among a group of people are independent. However, extensive research over the
past decades suggests otherwise. In this paper, a copula approach is used to
model the dependence between lifetimes within a married couple \eH{using data
from a large Canadian insurance company}. As a novelty, the age difference and
the \eH{gender} of the elder partner are introduced as an argument of the
dependence parameter. \green{Maximum likelihood techniques are} thus
implemented for the parameter estimation. Not only do the results make clear
that the correlation decreases with age difference, but also the dependence
between the lifetimes is higher when husband is older than wife. A
goodness-of-fit procedure is applied in order to assess the validity of the
model. Finally, considering several products available on the life insurance
market, the paper concludes with practical illustrations.
