Can the separation of a father and a mother affect a child's development
Yes it can affect the development of the child for different reasons. The effect could be
either a positive one or a negative one. It could be positive if the marriage is a toxic one.
There are no positives when a child is missing either parents. Nature designed parenting to be a joint ticket of sorts and when either parent is absent, the present parent can only fulfil their specific role in the upbringing of a child.
If a child grows up in a home where both parents are fighting each other and abusing themselves every time, it becomes a thing of fear and negative effects to the child. It is better for the child to leave such environment rather than growing in the same environment.
The chid may leave but the function, support and parenting role cannot be replaced because it is irreplaceable. For instance, when a small child is crying, parental link is responsible for the parent (father or mother) feeling the impact of the child's cry. This is not possible if the child doesn't biologically belong to the individual taking care of them. Sometimes, a psychologist can tell if you're a child's biological parent through such bonding mechanisms.
But the negative side of separation is more than the negative side of it. If the couples were to separate, the child firstly becomes an orphan then the child also grows up under a single parent which sometimes becomes a problem to them. A child normally needs the care of both parents, it is meant to be a combined effort between the two. Fostering a child from his infant stage up to the level of adulthood is never a small thing to do.
This is correct.