Extensive research defines the impact of advanced maternal age on couples’ fecundity and reproductive outcomes, but significantly less research has been focused on understanding the impact of advanced paternal age. Yet it is increasingly common for couples at advanced ages to conceive children. Limited research suggests that the importance of paternal age is significantly less than that of maternal age, but advanced age of the father is implicated in a variety of conditions affecting the offspring. This review examines three aspects of advanced paternal age: the potential problems with conception and pregnancy that couples with advanced paternal age may encounter, the concept of discussing a limit to paternal age in a clinical setting, and the risks of diseases associated with advanced paternal age. As paternal age increases, it presents no absolute barrier to conception, but it does present greater risks and complications. The current body of knowledge does not justify dissuading older men from trying to initiate a pregnancy, but the medical community must do a better job of communicating to couples the current understanding of the risks of conception with advanced paternal age.

No abstract

No abstract

Ab initio intermolecular potential energy surface, bound states, and microwave spectra for the van der Waals complex Ne-HCCCN The ground-state potential energy surfaces of Rg-N 2 and Rg-C 2 ͑where RgϭHe, Ne, or Ar͒ have been investigated at the coupled cluster singles, doubles, noniterative triples ͓CCSD͑T͔͒ level of theory using aug-cc-pVDZ and aug-cc-pVTZ basis sets. A basis set extrapolation procedure was employed to estimate the complete basis set limit, and the extrapolated potential energy surface was then utilized to calculate the bound intermolecular states and microwave transition frequencies of each complex. The Rg-N 2 complexes were chosen to demonstrate the reliability of the extrapolation scheme, since there are abundant theoretical and experimental data already available for these complexes. The calculated binding energies and equilibrium structures of the Rg-N 2 complexes compare favorably with previous semiempirical and ab initio calculations. The calculated microwave transition frequencies for Ar-N 2 are in excellent agreement with experimental values ͑deviation Ͻ0.1% rms) whereas the equivalent Ne-N 2 transitions show a greater deviation ͑1.3% rms͒. There are currently no experimental data with which to compare the binding energies and rovibrational energy levels of the Rg-C 2 complexes. However, the rovibrational energy level predictions should serve as a useful guide to any future spectroscopic studies of Rg-C 2 complexes.

No abstract