When does the influence of heredity begin?

The influence of heredity begins prior to conception through the genetic materials contributed by the parents. This means that the genetic information that determines many of a child's physical traits, health predispositions, and even some aspects of behavior is established at the moment of conception, when the sperm and egg come together to form a zygote. This genetic foundation is carried throughout a person's life, influencing growth and development from the earliest moments.

Although other stages of life, such as birth or early childhood, also play crucial roles in development, these phases primarily involve environmental influences and the effects of experiences as the individual grows. Thus, heredity’s influence is established well before these stages, making the timing of genetic contribution from the parents critically important in understanding the overall process of development.