My post, Science Supports Biblical Marriage, presents scientific evidence that one man married to one woman is associated with better pregnancy outcomes, where repeated sexual intercourse between husband and wife brings about change in the women such that her womb is a safer place for their babies. Now there is science which provides interesting evidence supporting the Biblical teaching of husband and wife becoming one.
It has been discovered that when a women carries a child in her womb, some of the child’s DNA crosses through the placenta and becomes a more or less permanent part of the the woman’s DNA. (for some details of this evidence see the notes below) Since the the child’s DNA is a composite the father’s and the mother’s DNA, when a man and women have a child together, the women ends up with some of the father’s DNA becoming part of her physical being. Through procreation a man and women become physically more similar to one than they were before.
In Genesis 2:24 it says,
a man shall leave his father and mother and be joined to his wife, and they shall become one flesh. (NKJV)
Commentators say the husband and wife becoming one flesh refers to the profound connected-ness and commitment intended in the marriage relationship, which is true. Now the scientific evidence provides an additional and fuller meaning to “becoming one flesh.” Once a couples sexual relationship results in children, they will physically share some actual sequences of DNA, becoming more genetically “one” than they were before.
The Sharing of DNA cannot be the whole story for the sexual bond is designed to form a connected-ness between the man and the women that is present even if the couple cannot have, or do not have, children. The apostle Paul tells us in 1 Corinthians 6:16 that sex with a prostitute also leads to the two in some way becoming one. This oneness is associated with the sexual consummation of the relationship. Nothing is said about having children. Yet, this truth does not diminish the amazing truth about the additional physical oneness science has found to occur between husband and wife through procreation.
This physical oneness will increase with each subsequent pregnancy have a man and women have together. Larger families increases the physical oneness.
Another interesting thought involves miscarriages. Although the science presented in the foot notes provides no direct proof, it is reasonable (and likely) to conclude the same thing happens with pregnancies which end in miscarriage, that they too lead to increased physical oneness between the husband and wife. This can be something positive in the midst of a very difficult situation.
Another situation where this sharing of DNA has implications is related to modern fertility practices which have allowed women to carry a child in her womb who is the product of a man other than her husband or even other than both herself and her husband. Having carried such a child in her womb, this women will now have, as part of her physical being, some of the DNA from a man other than her husband and, in some cases, even from another women. Does this matter?
Before leaving this topic, let me ask you, “Are you surprised to find the exploration of science into truth, supporting Biblical teaching such as “a man should leave his father and mother, be joined to his wife, and the two should become one flesh.?” If, indeed, God created the heavens and the earth (Genesis 1:1), should we be surprised when study of earthly things (science) supports the Word of Him who created them? Consider the argument of the Apostle Paul in the book of The Acts of the Apostles 17:24-27
The God who made the world and everything in it, being Lord of heaven and earth, does not live in temples made by man, nor is he served by human hands, as though he needed anything, since he himself gives to all mankind life and breath and everything. And he made from one man every nation of mankind to live on all the face of the earth, having determined allotted periods and the boundaries of their dwelling place, that they should seek God, and perhaps feel their way toward him and find him. (NKJV)
I hope this encourages you to continue to “feel your way toward God,” who created all things and ultimately to “find Him.”
For those who are interested in more about science supporting the Word of God use for following links:
Science Supports Biblical Mariage
Science Supports The Word of God
 The placenta is what allows the mother’s blood to come along side the baby’s blood in the womb so that nutrients and other important things can pass from the mother to the baby. The placenta also allows some things from the baby’s blood to pass into the mother’s blood.
 An article that includes a number of scientific study references is “We are multitudes” by Katherine Rowland. The article can be found at this link : https://aeon.co/essays/microchimerism-how-pregnancy-changes-the-mothers-very-dna
The article, by journalist, Katherine Rowland, appears to be well researched, and provides a lot of supporting scientific evidence. Christians who read it may object as the article does have an evolutionary bias but this does not negated the evidence that the DNA of children, carried in the mother’s womb, becomes part of the mother. Katherine’s article is a commentary referenced by a number of studies. A reference to one of the studies titled, Male Microchimerism in the Human Female Brain, whose evidence I found compelling is included below. 
Katherine Rowland is a journalist. Her work has appeared in Nature, the Financial Times, the Independent, OnEarth and other publications. She is the publisher and director of Guernicamagazine, and lives in New York City.
 William Chan et al. Male Microchimerism in the Human Female Brain, PLOS, 2012. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0045592
– This study has some heavy reading. I have provided some of my own comments on this article can be found at the following link: https://greg.kenyonspage.ca/my-comment-on-male-microchimerism-in-the-human-female-brain/