Rich Fathers Are Never Too Old to Have a Child: A Lesson of the Past for the Present

Marco Breschi, University of Sassari
Matteo Manfredini, University of Parma
Alessio Fornasin, University of Trieste
Stanislao Mazzoni, University of Sassari

Male fertility has hardly been considered in the demographic literature. Theories formulated to explain changes in human fertility have seldom included men and empirical analyses of fertility have been characterised by a strong female-dominated tradition (Zhang 2011). Recent bio-medic literature suggests that increasing male age is associated with a decline in semen volume, sperm motility, and sperm morphology. Furthermore, significantly lower fecundability has been found even after controlling for maternal age and other confounding variables. Other factors, such as a good heath status, can be crucial in male fertility and fecundability. In this paper, we study this topic in a historical context. In particular, using detailed individual biographies that cover the whole reproductive life course, we calculate and compare male and female age-specific marital fertility rates for the Sardinian town of Alghero in the period 1866-1935. Thanks to micro-level analyses, we test the hypothesis that the “male effect" was more pronounced when health, and more in general the quality of life, was low. We find a crucial effect of male age (especially after the age of 50) and this is particularly true for the poorest and unhealthy individuals.

Richfathers are never too old to have a child: a lesson of the past for the present

 

MazzoniS., Breschi M., Fornasin A. and Mafredini M.

 

 

Introduction

Male fertility hashardly been considered in the demographic literature. Theories formulated toexplain changes in human fertility have seldom included men and empiricalanalyses of fertility have been characterised by a strong female-dominatedtradition (Zhang 2011). Recently, from a bio-medic perspective, the weight of theevidence suggests that increasing male age is associated with a decline insemen volume, sperm motility, and sperm morphology. Using time to conception asan index to measure male fecundity, a significant decline, correlated withadvanced paternal age, has been found even adjusting for maternal age and otherconfounding variables (Ford et al. 2000, Hassan, Killick 2003; Dunson, Baird,Colombo 2004). Other factors, such as a good heath status, can be crucial inmale fertility and fecundability (Delamater 2012; Karraker, DeLamater, Schwartz2011). In this paper, we study this topic in a historical context. Inparticular, using detailed individual biographies that cover the whole reproductivelife course, we calculate and compare male and female age-specific maritalfertility rates for the Sardinian town of Alghero over the period 1866-1935. Thanksto micro-level analyses, we test the hypothesis that the “male effect" wasmore pronounced when health, and more in general the quality of life, was low.

 

The studied area

 

The studied area is thetown of Alghero. Fertility, during the studied period, is roughly notcontrolled and does not decline much (Breschi et al. 2014). The population ofAlghero controls marriage behaviour (late marriages and high levels of celibacyamong both men and women) to limit the total number of births and adapt thisnumber to the available resources (Corridore 1902; Breschi et al. 2014). InSardinia (and in Alghero) total fertility rate was much lower than the nationalaverage while, at the opposite, married couples had a high marital fertilityand started to reduce family’s size later than in other areas of the country(Livi Bacci 1977).

The health status ofAlghero’s population was very poor, as seen by the extremely high incidence of(permanent and temporary) discharge of young men from military service,accounting for over 50% of the cohorts born between 1866 and 1900 at firstenrolment (Breschi et al. 2011). However, SES reflects different livingconditions and a disparity of resources among the groups.

 

Male fertility (firstresults)

 

Fertility is mainly drivenby woman age but the influence of male age is clearly detectable: we find boththe effects of increasing male age and age difference between spouses. Infigure 1 we show the second effect comparing peer couples with couples wherethe groom is ten years older than the bride and controlling for bride age atmarriage.

 

Fig. 1. Specific marital fertility rates. Bride (20-24 years old)with “peer groom” and “ten years older groom” (left). Bride (25-29 years old)with “peer groom” and “ten years older groom” (right).

 

The difference betweenpeer couples and couples with an “older man” amounts to almost one child in thetotal marital fertility rate. After a detailed descriptive session, we extendour analyses in a micro level perspective using birth intervals in order toexplore the effect of male age on the risk of having another child. We control multivariatemodels with different covariates: period, marital duration, woman age, maritaltype (first or remarriage), previous child outcome – an important factor inSardinia – and SES. Outcomes confirm the results of the descriptive part stressingthe crucial effect of the male biological clock, especially after the age of50. Moreover, we find SES differentials: “rich fathers”, thanks to a betterquality of life and health, could maximise the biological resources of the couplewhile the poorest individuals had to pay for the price of a stunted and unhealthylife.

Presented in Session 1059: History