Richard Hanania tackles a provocative question that most parents hope never to ask: does the technology used to create a child actually make them worse off? While the debate around embryo selection often fixates on ethics or cost, Hanania pivots to a biological variable rarely discussed in mainstream parenting circles: the loss of natural sperm competition. This piece is notable not for its conclusion, but for its rigorous dismantling of the assumption that 'natural' always means 'superior' in the context of assisted reproduction.
The Myth of Natural Superiority
Hanania begins by challenging the intuition that the sheer volume of biological competition in natural conception guarantees a better outcome. He notes that in natural conception, tens of millions of sperm compete, with only one emerging victorious. In contrast, modern fertility treatments often bypass this gauntlet entirely. He writes, "In nearly all imaginable semen samples, IVF selects for another phenotype of spermatozoon to fertilize the oocyte than coitus does." This distinction is crucial because it suggests the selection criteria have fundamentally shifted from a high-stakes biological race to a laboratory-based selection process.
The author draws on historical context regarding Intracytoplasmic sperm injection (ICSI), a technique that has become the default for about three-quarters of IVF cases. He points out that in ICSI, a technician manually injects a single sperm into an egg, effectively removing the selection pressure on the sperm to "localize an oocyte in its immediate surroundings." Hanania argues that this artificial intervention is a double-edged sword. "The second method, which has almost no selection mechanism, is the default way of doing IVF," he observes, questioning whether bypassing the evolutionary filter of natural selection leaves the resulting child at a disadvantage. Critics might note that this framing assumes natural selection is always optimizing for human health, ignoring that it often selects for traits that are merely reproductively successful, not necessarily healthy in a modern context.
"You would think that a process involving hundreds of millions of competitors with a single victor is going to end up with a better result than simply choosing a winner based on superficial criteria."
The Data on Health Outcomes
Moving from biological theory to empirical evidence, Hanania scrutinizes the health data of children born via Assisted Reproductive Technology (ART). He acknowledges that early studies suggested a link between IVF and higher rates of birth defects or behavioral issues. However, he argues these findings are often statistical artifacts caused by the underlying health of the parents. "People generally seek out IVF because they have trouble conceiving, which could itself indicate health problems," he explains. When studies fail to control for parental subfertility, they mistake the cause of the child's health issues as the procedure itself rather than the genetic or biological hurdles the parents faced.
Hanania highlights a meta-analysis by Rimm et al. that initially found a 29% higher chance of major malformations in IVF children. Yet, when the researchers adjusted for parental fertility issues, the effect vanished. "Once this was adjusted for, there was no effect of IVF on major malformations," Hanania writes. This is a powerful example of how easily data can be misinterpreted without proper controls. He further notes that even in sibling studies—where one child is born naturally and another via IVF—the differences are often negligible. "When you measure against population controls, you get a handful of statistically significant negative health results, and all but one disappear in the comparison to siblings," he concludes regarding a large UK study. The evidence suggests that the process of IVF itself is not the primary driver of health deficits; rather, it is the biological context of the parents seeking the treatment.
Cognitive Ability and the Socioeconomic Filter
The argument extends to cognitive outcomes, where the data reveals a different kind of bias. Hanania examines studies from Finland and Denmark that initially showed IVF children performing better academically or having higher IQs. However, these advantages disappear when controlling for the socioeconomic status of the families who can afford these treatments. "In Denmark, 15- and 16-year-olds born through MAR have higher IQs than the general population by about 0.2 standard deviations, but when controlling for them being higher socioeconomic status, they are actually 0.1 SD below children born into similar environments," he notes.
This finding reinforces the idea that the environment and resources provided by the parents, not the method of conception, are the dominant factors in a child's development. Hanania writes, "The results were attenuated when controlling for demographic factors between families, and then completely disappear when comparing siblings." This suggests that the perceived 'superiority' of IVF children is often a reflection of the privileged circumstances of their families rather than a biological advantage gained through embryo selection. The only area where a consistent negative effect remains is birth weight and preterm birth, a known risk of the medical procedure itself, but even this is a matter of degree rather than a fundamental deficit in the child's potential.
"All of this teaches us that we need to be very careful when interpreting data on this issue, even when papers control for factors other than subfertility."
Bottom Line
Richard Hanania's analysis effectively separates the biological mechanics of conception from the statistical noise of parental health and socioeconomic status. His strongest argument is the demonstration that when proper controls are applied, the fear of 'deficient' IVF children is largely unfounded. The piece's biggest vulnerability lies in its reliance on the assumption that natural sperm competition is an optimal filter for human health, a premise that evolutionary biology does not fully support. For busy parents weighing the pros and cons of embryo selection, the takeaway is clear: the technology itself is not the enemy, and the data does not support the idea that natural conception guarantees a healthier or smarter child.