Читать книгу Infants and Children in Context - Tara L. Kuther - Страница 165

It is easy to see how mothers’ health, behavior, and contexts influence prenatal development, but what about fathers? It was once thought that fathers had no influence on prenatal development and researchers thus neglected to study the father’s role. Most obviously, fathers influence the home context. Second-hand smoke from fathers is harmful to the developing organism (Wang et al., 2018). Fathers’ interactions with pregnant mothers can increase maternal stress, with potential negative implications for prenatal development. We know less about how fathers’ health, behaviors, and contextual factors act as biological influences on prenatal development.

Advanced paternal age is associated with an increased risk of birth defects, chromosomal abnormalities, Down syndrome, and autism spectrum disorder (Day, Savani, Krempley, Nguyen, & Kitlinska, 2016; Herati, Zhelyazkova, Butler, & Lamb, 2017). Paternal alcohol and substance use and exposure to toxins such as lead can impair sperm production and quality (Borges et al., 2018; Estill & Krawetz, 2016). For example, smoking is associated with DNA damage and mutations in sperm (Beal, Yauk, & Marchetti, 2017; Esakky & Moley, 2016).

In addition to DNA, fathers (and mothers) also pass on epigenetic marks that can influence their offspring’s health throughout life and may even be passed to their offspring’s children. Recall from Chapters 1 and 2 that the epigenome determines how DNA is expressed, what genes are turned on and off. The epigenome contains a molecular record or “memory” of a person’s life experiences, including health behaviors, exposure to toxins, nutritional status, and more (Abbasi, 2017). Moreover, epigenetic marks are heritable, passed through ova and sperm, meaning that they can be inherited from parents or even grandparents (Immler, 2018). Exposure to substances and contaminants can alter the epigenome that is passed to offspring and potentially from generation to generation (Bošković & Rando, 2018). For example, in one study, men whose fathers smoked when they were conceived had a 50% lower sperm count than the men with nonsmoking fathers (Axelsson et al., 2018). It is important to remember, however, that the epigenetic marks we are born with are not set in stone. Some epigenetic marks can be changed after birth through experiences, health care, and behaviors such as diet and exercise (Champagne, 2018).