I am normal and can be trusted with the knowledge of the stars

On an average, assuming genetic invariability with reference to allosomes (which can be premediated via presence or lack of the Y Chromosomes which can be identified by a simple blood test, yadda yadda yadda), you're talking an average of 8 weeks for the pregnancy to be readable enough in re sex of the kid. (Assuming the kid is Cisgendered.) This is typically followed by 9 months of pregnancy (- the 8 weeks) and about 18 months of recommended recovery period after. This gives the conception and birth of each kid an average timeline of 27 months in all, which is about 2.25 years.

Now, in re Lou Bega's Mambo No. 5, there are a total of 9 individuals mentioned. Angela, Pamela, Sandra, Rita, Monica, Erica, Rita (repeated), Tina, Sandra (repeated), Mary, and Jessica. Assuming the existence of a singular Rita and Sandra which were called upon twice in the song, we can assume that this would involve a grand total of 2.25 x 9 = 20.5 years of near constant pregnancies to produce the offspring in question.

Assuming that the embryonic host typically hits Menopause at around 40, we can assume that the primary conception in re the same occurs at around 19.5 years of age. Which is still premature in re sociocultural aspects but the body is more than capable of handling such a strain at that age.

Also, in case we assume that every one of the offspring remain in all cases, cisgendered (which is a variable that is very hard to account for), we can assume that there is always a possibility that the allelomorph of the embryo involved can occasionally involve an XY chromosome. The detection can successfully occur at 8 weeks, and in case an abortion ensues, conception can recur within as little as 2 more weeks. That is an added extra 10 weeks per in re the nondesired sex.

In case of purely clinical states, such as IVF, where the Ova are extracted and externally fertilised each time, a system of Preimplantation Genetic Testing for Aneuploidies (PGT-A) can be incorporated in order to identify XX chromosomal situations and ensuring further that only those are implanted. This, while making sure that the offspring in question are necessarily of the XX karyotype, cannot of course state whether a state of monozygotic twinning can occur or not. More often than not, in order to maximise chances of implantation, more than two embryos used to be implanted into the uterus, typically around five. But technology has significantly improved in the years following which makes sure that there is no need for the same. Elective Single Embryo Transfer (eSET) is now the standard in modern IVF, prioritizing the transfer of one, high-quality, genetically tested blastocyst to achieve a healthy, single-baby pregnancy. This shift minimizes severe risks associated with multiple pregnancies, such as preterm birth for babies and severe complications for mothers, while maintaining high success rates. Clinics now reserve multiple embryo transfers primarily for older patients or those with histories of repeated IVF failures, rather than routine practice.

In case there are more than one embryos that get implanted that are undesirable, the extra embryos can be removed through a medical procedure called multifetal pregnancy reduction (MFPR) or selective reduction.

In summation, assuming of course that we are talking about the most clinically ideal circumstances, where there is the implantation of a single embryo each time, that still gives you about the same timeline of about 20.5 years. In case of preferring to determine sex after (which is cheaper) as opposed to before (which is still pricey as fuck in today's economy), that adds another 10 weeks per embryo. Unwanted implants can be removed via MFPR.