Further implications one parent (usually the mother) promoting plasticity and the

4.2. Further implications one parent (usually the mother) promoting plasticity and the

other (usually the father) promoting the development of a While the consequences of mother-fetus conflict are usually more fixed phenotype. Of course, the biological interests of

constrained by the reciprocal interaction between opposing an absent father may be furthered by paternal kin, as well as

physiological mechanisms, there may be occasions in which by paternally expressed genes in the offspring’s genome conflict imposes severe costs on one or both parties. For

(Section 3.3 ).

various reasons (including high genotypic susceptibility of the The discovery that parent-offspring interactions are fetus), the physiological arms race between mother and fetus intrinsically driven by conflict as well as altruism ( Trivers, may sometimes escalate beyond control, resulting in a net 1974 ) has been a major propulsive force in evolutionary fitness cost for the mother, the fetus, or both. For example, biology. After a long delay, this perspective is starting to

prenatal conflicts in the regulation blood glucose (Section make way in psychology ( Schlomer et al., 2011 ). In the field

1.2.1 ) sometimes end up causing gestational diabetes, a of prenatal development, however, the logic of parent-off-

dangerous condition that increases the risk for later health spring conflict is still not widely appreciated, despite its problems, both in the mother and the fetus (e.g., Haig, 1993; remarkable explanatory and heuristic potential. That Boney et al., 2005; Feig et al., 2008 ). This suggests the

between the mother and the developing fetus is one of intriguing possibility that the severe, fitness-reducing pathol- the most vital, intimate, and complex relationships between

ogies associated with prenatal stress — including autism and two living beings. In order to fully understand it, we need to

schizophrenia — may actually represent the side effects of appreciate how conflict and cooperation can go hand in hand,

escalated conflict. In other words, the increased risk for and learn to look for their traces in the dazzling intricacy of

severe psychopathology following maternal stress might physiological mechanisms.

not be a ‘‘design feature’’ of prenatal programming (as

suggested by Glover, 2011 ), but rather an occasional mala- Role of funding source

daptive consequence of the conflictual interplay between

No funding declared. understanding of

adaptive mechanisms in the mother and fetus. This seems a

worthy topic of future research: a better

the side effects of prenatal conflict would greatly help in

drawing the line between adaptive and maladaptive out- Conflict of interest

comes of fetal programming (Section 1.1.2 ), and may even-

tually lead to devise effective prevention strategies. No conflict declared.

On a more general level, the conflict perspective devel-

oped here has far-reaching implications for theories of devel- Acknowledgment

opmental plasticity. Belsky (1997, 2005 ; see also Ellis et al.,

I wish to thank David Haig, Tobias Uller, Bruce Ellis, Jay (i.e., differential plasticity) is adaptive for both parents

2011 ) proposed that differential susceptibility to rearing

Belsky, and Michael Pluess for their useful comments and

and children, because less susceptible children are also less constructive criticism on previous versions of the manuscript.

likely to suffer from fitness-detrimental parental influences.

While parents attempt to shape their offspring’s phenotype

so as to match future environmental conditions, their pre- References

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