Previous studies on the status and changes in the timing and universality of marriages among Iranian women have had a single-sex approach and provided analysis based on the data only of women's marriages. However, the prevalence of marriage among women depends on the demand of the opposite sex, and men's desire to marry determines their marriage demand. With such an approach and using data from the civil registration system on the age of women at marriage by age of their partners and two-sex nuptiality life table, we estimate the marriage demand of men using men's table and by calculating the probability of marriage of women for each age range, the number of survivors has been projected at any age with a generational perspective. Results show that in the last two decades, mainly due to the increase in the age of marriage for men, the postponement of women's marriage from the 20s to the 30s has increased the total number of single survivors aged 30 and over and decreased the universality of marriage. Based on the generational projection of this article, definite celibacy (ratio of people who have never been married until the age of 50) of women will be increasing from less than 5% for the generation that reached 50 years old in 2016 to more than 20% for the generation that reaches this age in 1435. Accordingly, for a generation that reaches the age of 10 in 2016, if women marry only once, about a quarter, and if there is a proposal from divorced men, about a fifth of them will never marry until the age of 50