This answer is in two parts explaining first, the probabilities involved in passing genes from one generation to the next and then reaching a conclusion to answer the question.
The Inheritance of IQ
In 2011, a large group of researchers published the results of a genome-wide analysis of 549,692 single nucleotide polymorphisms (SNPs) involving 3511 unrelated adults. (An SNP represents a difference in a single DNA building block, called a nucleotide.) (See: Davies, G., A. Tenesa, A. Payton, J. Yang, S.E. Harris, D. Liewald, et al. 2011. “Genome-wide association studies establish that human intelligence is highly heritable and polygenic.” Molecular Psychiatry. 16. pp. 996–1005.) They reported:
Our results unequivocally confirm that a substantial proportion of individual differences in human intelligence is due to genetic variation, and are consistent with many genes of small effects underlying the additive genetic influences on intelligence. … [Furthermore] purely genetic (SNP) information can be used to predict intelligence.
This research estimated the heritability of IQ to be about 0.5, confirming the results of the studies involving twins. Its conclusion that general intelligence is polygenic, i.e., it derives from a combination of many genes supports the concept of intelligence as a multi-faceted characteristic. In his 2016 book, The Gene: An Intimate History, Siddhartha Mukherjee wrote:
While some combination of genes and environments can strongly influence g, this combination will rarely be passed, intact, from parents to their children. Mendel’s laws virtually guarantee that the particular permutation of genes will scatter apart in every generation. … . Intelligence, in short, is heritable (i.e., influenced by genes), but not easily inheritable (i.e., moved down intact from one generation to the next).
Mukherjee is arguing that since g is polygenic, and is derived from a random selection from two parents, a specific combination of genes in either parent has a low probability of passing intact to the offspring. For example, imagine that each of your parents has n alleles that combine at your conception to form your intellectual potential. Think of these alleles as a hand of n playing cards, of which about one-third are face cards if your parents are of average intelligence. During your conception n/2 cards are drawn from each parent. If the cards you draw from both parents are mainly face cards, you will have more intellectual potential than either parent and your potential IQ would be much greater than theirs. Of course, you would need to involve yourself in deep learning and challenging intellectual pursuits in order to reach that potential IQ.
Studies showing that the IQs of siblings have only a moderate correlation (about 0.47) support this model of inheritance. Traits that are defined by a complex combination of genes are less likely to be passed from one generation to the next intact. Hence height, governed by fewer alleles, has high heredity, while intelligence and temperament, governed by more alleles, have a lower heredity. Of course, if you do attain an IQ of 160, you will find that it comes with some inherent dangers, as explained in What danger threatens those of high IQ? – Intelligence and IQ
If you are more intelligent than your parents, can you have children of IQ lower than your parents?
The short answer is “yes.” If you and your spouse have lots of alleles in your DNA that favor high intelligence, then the odds are in favor of your offspring having a high IQ. That is, you’ve “stacked the deck” in your children’s favor. However, it is also possible that your children will not draw your “face cards” and may have a lower IQ than you and your spouse. Everything boils down to probabilities, but if both parents have a high intelligence, the probabilities are stacked in favor of intelligent offspring.
