伴侣怀孕时，男性真的易出轨吗？

A new study found that men show shifts in behavior from mating-oriented to parent-oriented while their partners’ pregnancy develops. These changes are determined by changes in testosterone levels across pregnancy and hormonal linkage with their partner。
一项新的研究发现，在伴侣怀孕时，男性的行为会从交配导向型转变为家长导向型。决定这一转变的是伴侣怀孕期间男性睾丸素水平的变化，以及他们与伴侣之间的荷尔蒙联动。

It’s almost hard to imagine that every caring dad was once a skirt-chasing ball of hormones — but it’s true. Somewhere along their transition to parenthood, biology puts a stop to men’s carefree days of sowing wild oats and turns their attention towards nurturing children. This is a very solid strategy from an evolutionary point of view, but we didn’t know exactly how it happened.
难以想象每个慈爱的爸爸都曾是一团追逐女性的荷尔蒙——但这是真的。在转变为人父的过程中，生物机制使男性结束了逍遥自在、四处播种的日子，并将注意力转到养育孩子上。从进化的角度来看，这是一个非常可靠的战略，但我们并不确切知道它是如何发生的。

A new study found that the answer may be testosterone. While high levels of this androgenic steroid hormone have been associated with aggression and competitive behavior, lower levels promote nurturing behaviors, particularly those related to caring for offspring.
一项新的研究发现，答案可能是睾丸素。尽管高水平的这种雄性类固醇激素与侵略性和竞争性行为有关，低水平时则促进养育性行为，特别是那些与照顾子女相关的行为。

Previous studies show that fathers who are in a relationship and are more involved with children’s care show lower testosterone levels that men who don’t have children. Lower levels of salivary testosterone have also been tied to higher self-reported levels of relationship satisfaction and commitment, a lower interest in sex outside of marriage and a lower chance of divorce. So it would seem that a father’s decrease in testosterone levels during the transition to parenthood leads him from exploring new mating opportunities towards investment into the current relationship and caring for offspring.
之前的研究表明，处在一段亲密关系中且更多地参与照看孩子的父亲，其睾丸素水平低于没有孩子的男性。与低水平的唾液睾酮相关的是较高水平的爱情满意度和忠诚度，男性对婚外性的兴趣较低，离婚的几率也较低。因此，似乎在向人父转变的过程中，父亲的睾丸素水平下降，会使其停止寻求新的交配机会，投身于目前的关系及照顾后代。

Led by Darby Saxbe of the University of Southern California, the study followed 27 couples expecting their first child during pregnancy and first few months after birth. The parents’ testosterone levels were measured during this pregnancy, and participants rated their investment, commitment, and satisfaction with their partner a few months after their child’s birth.
这项研究由南加州大学的Darby Saxbe带领，他们追踪了27对夫妻怀第一胎以及孩子出生后几个月里的情况。他们测量了在怀孕期间家长们的睾丸素水平。孩子出生后的几个月中，参与调查的夫妻还要对自身的投入度，忠诚度和对伴侣的满意度进行打分。

The team found that fathers showed significant declines in testosterone while the pregnancy progressed, and a significant positive correlation with the mother’s testosterone levels. A better correlation between the mother’s and father’s testosterone levels during pregnancy was associated with higher levels of father involvement after the child’s birth — the degree of synchrony between the parents predicted the fathers’ investment, commitment, and satisfaction in the couple relationship.
该研究小组发现，在伴侣怀孕期间，父亲的睾丸素水平出现明显的下降，并且与母亲的睾丸素水平呈显著的正相关。在怀孕期间母亲和父亲的睾丸素水平之间的相关性越好，孩子出生后父亲的参与程度越高——父母之间的同步程度预示着父亲的投入度、忠诚度和对夫妻关系的满意度。