Oddly enough, there may be some biological truth in there, though she misunderstands it.
To start with, men have the basic biological prerogative to spread their DNA around, resulting in offspring from several different women. Women, on the other hand, have the double basic biological prerogative to get the best male DNA donor, *and* a male who will be best at providing for her offspring. And when there are more than a minimum number of men, these are usually not the same two men.
But this is basic biology. Humans innovated socially enforced marriage, which gives a better outcome to children, women and men than does basic biology, even monogamous biology.
Marriage helps assure men that the children his wife has, have his DNA, for which he gives up on having multiple female partners. In exchange, the woman is given some assurance that her husband will not make children with other women, splitting his provision between them, however she accepts that neither his DNA nor his provision will be the best, just adequate.
And marriage definitely helps children, because a two parent family raises children oriented to success and prosperity; whereas a single parent child is raised to a survival orientation, a much harder life, which is why they have a 60% greater chance of becoming a criminal offender.
However, marriage has two problems outside of the family. The first of these is the dowry, that girl’s families do not select mates for their DNA and prosperity, but to enrich her family, not the couple and their children. This results in very bad couplings between elderly men and very young girls.
The other problem is that many people are neither designed to breed, nor, according to biology, should they. However, they still *want* to breed, and thus interfere with the married couple and their children.
Now all of this is background to explaining why biology itself has come up with means to distract the non-breeders, to prevent this interference. This includes a litany of tricks, possibly including homosexuality, prostitution, and sexual aggression in postmenopausal women.
But again, these are just basic biological tricks, and humans should come up with a better means for non-breeders to quit interfering with the breeders. This does not have to be oppressive, but it does have to be clear that while non-breeders are mostly still compelled to want sex, they should “keep it to themselves” and others like them, who also should not be breeding, or raising children for that matter.
“...best male DNA donor, *and* a male who will be best at providing for her offspring. And when there are more than a minimum number of men, these are usually not the same two men.”
Does that suggest that good DNA and success in providing for offspring are unrelated? It appears to be a contradiction. The best overall indicator for potential success in our culture is IQ, and there is most certainly a genetic component.
Women also have a biological drive to vary the genes of their offspring. It’s the perfect flip-side of the male drive to distribute seed. Several recent studies have confirmed this.
This is a nonsense statement. A dowry is provided by the bride's family and a girl with a substantial dowry would have her pick of spouses, not be married off to an old man. Depending on the culture, the dowry may indeed go to the couple and be the bride's personal property and not enrich the groom's family.
It is cultures where brides must be purchased that young girls end up with old men. This is frequently seen in polygynous societies because older, wealthier men with multiple wives create a scarcity of women in the marriage market and drive up the average cost of a bride.