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Telomere length (TL) has been associated with aging and mortality, but individual differences are also influenced by genetic factors, with previous studies reporting heritability estimates ranging from 34 to 82%. Here we investigate the heritability, mode of inheritance and the influence of parental age at birth on TL in six large, independent cohort studies with a total of 19,713 participants. The meta-analysis estimate of TL heritability was 0.70 (95% CI 0.64-0.76) and is based on a pattern of results that is highly similar for twins and other family members. We observed a stronger mother-offspring (r=0.42; P-value=3.60 × 10(-61)) than father-offspring correlation (r=0.33; P-value=7.01 × 10(-5)), and a significant positive association with paternal age at offspring birth (β=0.005; P-value=7.01 × 10(-5)). Interestingly, a significant and quite substantial correlation in TL between spouses (r=0.25; P-value=2.82 × 10(-30)) was seen, which appeared stronger in older spouse pairs (mean age ≥55 years; r=0.31; P-value=4.27 × 10(-23)) than in younger pairs (mean age<55 years; r=0.20; P-value=3.24 × 10(-10)). In summary, we find a high and very consistent heritability estimate for TL, evidence for a maternal inheritance component and a positive association with paternal age.

PurposeTo examine current evidence of the known effects of advanced paternal age on sperm genetic and epigenetic changes and associated birth defects and diseases in offspring.MethodsReview of published PubMed literature.ResultsAdvanced paternal age (> 40 years) is associated with accumulated damage to sperm DNA and mitotic and meiotic quality control mechanisms (mismatch repair) during spermatogenesis. This in turn causes well-delineated abnormalities in sperm chromosomes, both numerical and structural, and increased sperm DNA fragmentation (3%/year of age) and single gene mutations (relative risk, RR 10). An increase in related abnormalities in offspring has also been described, including miscarriage (RR 2) and fetal loss (RR 2). There is also a significant increase in rare, single gene disorders (RR 1.3 to 12) and congenital anomalies (RR 1.2) in offspring. Current research also suggests that autism, schizophrenia, and other forms of “psychiatric morbidity” are more likely in offspring (RR 1.5 to 5.7) with advanced paternal age. Genetic defects related to faulty sperm quality control leading to single gene mutations and epigenetic alterations in several genetic pathways have been implicated as root causes.ConclusionsAdvanced paternal age is associated with increased genetic and epigenetic risk to offspring. However, the precise age at which risk develops and the magnitude of the risk are poorly understood or may have gradual effects. Currently, there are no clinical screenings or diagnostic panels that target disorders associated with advanced paternal age. Concerned couples and care providers should pursue or recommend genetic counseling and prenatal testing regarding specific disorders.

It is not controversial to state that parental age is increasing in several countries. But how to deal with this increase might be. Some Nordic countries have set an upper age limit for females seeking assisted reproduction in their national legislation, but none have done so for males. There are also recommendations in place that restrict access to publicly funded assisted reproduction for both females and males of advanced age in some Nordic countries. As recent data now show somatic and psychiatric health risks related to advanced paternal age, we ask if the time has come for countries to set an upper age limit for males seeking assisted reproduction like there already is for females, and summarize some of the risks and rewards involved in treating couples with advanced age in fertility clinics.

It remains unclear whether there is an independent association of paternal age with implantation failure (IF) in couples undergoing Assisted Reproductive Technology (ART) treatment. Little is known about the interactive effects of paternal age with maternal age, paternal smoking and alcohol consumption on IF. The Anhui Maternal-Child Health Cohort Study (AMCHS) interviewed 1910 infertile couples (paternal age ranged 22–57 years) to look for risk factors associated with IF. Implantation outcome was assessed using serum β-HCG between 0 and 25 IU/L 14 days post-embryo transfer. Odds ratios (ORs) for IF in relation to paternal age, and its interactions with maternal age, paternal smoking and alcohol consumption were evaluated using logistic regression models. The risk of IF ( n  = 735) increased with paternal age ≥ 35, while it remained similarly lower among males aged 22–34. After adjusting for socioeconomic status,  paternal lifestyles and semen factors, the OR for IF was 1.50 (95%CI 1.16–1.93) at paternal age of 35-<40 years, 2.06 (1.34–3.16) at 40-<45 years and 3.80 (2.50–7.07) at ≥ 45 years in comparison to those aged < 35. With additional adjustments for maternal age and maternal factors including anovulation and antral follicle counting, the corresponding ORs were 1.19 (0.89–1.60), 1.31 (0.79–2.16) and 2.13 (1.06–4.29). The association remained significant in those with maternal age > 30, paternal smoking or alcohol consumption, but not in their counterparts, respectively. Among those with a paternal age ≥ 35, each additional year of smoking was associated with a 7.0% increased risk of IF (OR = 1.07, 95% CI: 1.01–1.14); however, no such association was observed in younger paternal age groups. Significant interaction effects were observed between advanced paternal age and maternal age, as well as paternal alcohol consumption. The AMCHS had demonstrated that paternal age ≥ 35 years elevates the risk of IF, with additional impacts from advanced maternal age and paternal alcohol consumption. The findings of the AMCHS highlight the need to consider paternal and maternal ages in fertility planning and suggest that IF can be reduced by stopping paternal smoking and alcohol consumption.

Advanced paternal age has been overlooked, and its effect on fertility remains controversial. Previous studies have focused mainly on intracytoplasmic sperm injection (ICSI) cycles in men with oligozoospermia. However, few studies have reported on men with semen parameters within reference ranges. Therefore, we conducted a retrospective cohort study analyzing the reproductive outcomes of couples with non-male-factor infertility undergoing in vitro fertilization (IVF) cycles. In total, 381 cycles included were subgrouped according to paternal age (<35-year-old, 35-39-year-old, or ≥40-year-old), and maternal age was limited to under 35 years. Data on embryo quality and clinical outcomes were analyzed. The results showed that fertilization and high-quality embryo rates were not significantly different (all P > 0.05). The pregnancy rate was not significantly different in the 35-39-year-old group (42.0%; P > 0.05), but was significantly lower in the ≥40-year-old group (26.1%; P < 0.05) than that in the <35-year-old group (40.3%). Similarly, the implantation rate significantly decreased in the ≥40-year-old group (18.8%) compared with that in the <35-year-old group (31.1%) and 35-39-year-old group (30.0%) (both P < 0.05). The live birth rate (30.6%, 21.7%, and 19.6%) was not significantly different across the paternal age subgroups (<35-year-old, 35-39-year-old, and ≥40-year-old, respectively; all P > 0.05), but showed a declining trend. The miscarriage rate significantly increased in the 35-39-year-old group (44.8%) compared with that in the <35-year-old group (21.0%; P < 0.05). No abnormality in newborn birth weight was found. The results indicated that paternal age over 40 years is a key risk factor that influences the assisted reproductive technology success rate even with good semen parameters, although it has no impact on embryo development.

PurposeTo study the impact of advanced paternal age on embryo aneuploidy.MethodsThis is a multicenter international retrospective case series of couples undergoing assisted reproduction via in vitro fertilization using donor eggs to control for maternal factors and preimplantation genetic testing for aneuploidy via next-generation sequencing at Igenomix reproductive testing centers. The main outcome measure was the prevalence of embryo aneuploidy in egg donor cycles. Semen analysis data was retrieved for a small subset of the male patients.ResultsData from 1202 IVF/ICSI egg donor cycles using ejaculated sperm (total 6934 embryos) evaluated using PGT-A between January 2016 and April 2018 in a global population across all Igenomix centers were included. No significant association was identified between advancing paternal age and the prevalence of embryo aneuploidy overall and when analyzing for each chromosome. There was also no significant association between advancing paternal age and specific aneuploid conditions (monosomy, trisomy, partial deletion/duplication) for all chromosomes in the genome.ConclusionsThis is the largest study of its kind in an international patient population to evaluate the impact of advancing paternal age on embryo aneuploidy. We conclude there is no specific effect of paternal age on the prevalence of embryo aneuploidy in the context of embryo biopsies from egg donor cycles.

Almost all countries and fertility clinics impose age limits on women who want to become pregnant through Assisted Reproductive Technologies (ART). Age limits for aspiring fathers, however, are much less common and remain a topic of debate. This article departs from the principle of reproductive autonomy and a conditional positive right to receive ART, and asks whether there are convincing arguments to also impose age limits on aspiring fathers. After considering three consequentialist approaches to justifying age limits for aspiring fathers, we take in a concrete normative stance by concluding that those are not strong enough to justify such cut-offs. We reinforce our position by drawing a comparison between the case of a 39-year-old woman who wants to become a single mother via a sperm donor on the one hand, and on the other hand the same woman who wants to have a child with a 64-year-old man who she loves and who is willing to care for the child as long as he is able to. We conclude that, as long as appropriate precautions are taken to protect the welfare of the future child, couples who want to receive fertility treatment should never be limited on the basis of the age of the (male) partner. An absence of age limits for men would respect the reproductive autonomy of both the man and the woman.

The RAS proto-oncogene Harvey rat sarcoma viral oncogene homolog (HRAS) encodes a small GTPase that transduces signals from cell surface receptors to intracellular effectors to control cellular behavior. Although somatic HRAS mutations have been described in many cancers, germline mutations cause Costello syndrome (CS), a congenital disorder associated with predisposition to malignancy. Based on the epidemiology of CS and the occurrence of HRAS mutations in spermatocytic seminoma, we proposed that activating HRAS mutations become enriched in sperm through a process akin to tumorigenesis, termed selfish spermatogonial selection. To test this hypothesis, we quantified the levels, in blood and sperm samples, of HRAS mutations at the p.G12 codon and compared the results to changes at the p.A11 codon, at which activating mutations do not occur. The data strongly support the role of selection in determining HRAS mutation levels in sperm, and hence the occurrence of CS, but we also found differences from the mutation pattern in tumorigenesis. First, the relative prevalence of mutations in sperm correlates weakly with their in vitro activating properties and occurrence in cancers. Second, specific tandem base substitutions (predominantly GC>TT/AA) occur in sperm but not in cancers; genomewide analysis showed that this same mutation is also overrepresented in constitutional pathogenic and polymorphic variants, suggesting a heightened vulnerability to these mutations in the germline. We developed a statistical model to show how both intrinsic mutation rate and selfish selection contribute to the mutational burden borne by the paternal germline.

Previous studies reported an association between advanced paternal age at birth and increased risk for schizophrenia and bipolar disorder. While some hypothesize that this association is caused by de-novo mutations in paternal spermatozoa, others cite factors associated with psycho-social characteristics of fathers who have children at a late age. This study aims to test these hypotheses. A historical-prospective, population-based cohort study, performed by linking the Israeli Draft Board Registry and the Israeli National Psychiatric Hospitalization Registry (N = 916 439; 4488 with schizophrenia, 883 with bipolar disorder). Odds ratios (OR) and two-sided 95% confidence intervals (CI) were calculated by logistic regression models, using paternal age as predictor and risk for later hospitalizations for schizophrenia or bipolar disorder as outcome measure. Models were first fitted unadjusted, then adjusted for paternal age at birth of the first child. In the unadjusted model, offspring of fathers aged 45 and above at birth had increased risk of schizophrenia (OR = 1.71, 95% CI 1.49-1.99) and bipolar disorder (OR = 1.63, 95% CI 1.16-2.24). However, taking into account paternal age at birth of first child, advanced paternal age was no longer associated with increased risk of schizophrenia (OR = 0.60, 95% CI 0.48-0.79) or bipolar disorder (OR = 1.03, 95% CI 0.56-1.90). Controlling for paternal age at birth of the first offspring, advanced paternal age does not predict increased risk for schizophrenia or bipolar disorder. These data indicate that the association between advanced paternal age and having an offspring with schizophrenia and bipolar disorder is likely due to psychos-social factors, or common genetic variation associated with delayed initial fatherhood.

Background Research shows that the age of fathers at the time of conception is correlated with detrimental effect for the health of the future offspring. This situation raises ethical questions regarding the priority of the principle of reproductive autonomy of men of advanced age over the well-being of their future offspring. This problem leads to other normative implications such as the value of introducing limits to the use of medically assisted reproduction, and the development of public health interventions. For the moment, this ethical reflection is mostly speculative and calls to open up the discussion. The aim of this research was to survey experts, working in related fields to the topic of advanced paternal age (APA), regarding the top priority ethical issues of this emerging subject. Methods We recruited experts concerned by APA with backgrounds in health sciences, ethics, social work and reproductive medicine. We conducted a modified e-Delphi panel that lasted three rounds to build a consensual list of issues. The last round took the form of structured interviews exploring the results of the previous rounds. Results The top four issues according to the panel are: (1) Should APA be included as a criterion for prenatal genetic screening? (2) Should we raise awareness on reproductive health in relation to the age of fathers? (3) How can health-care providers support patients in the context of APA? (4) How can research inform the public without stigmatizing fathers of advanced age? Conclusions These exploratory results suggest that the issues of how to inform various audiences properly on APA are important concerns for experts. Clinical trial number Not applicable.