Population dynamics

A stabilised population growth rate is an insurance and investment for national development through availability of manpower as well as its productivity in the future. Conversely, a shrinking population is less productive to even support its aged as well as replenish the young stock in the uncertain tomorrow. In a competitive world, such a latter population is easily weeded out eventually. Therefore, a healthily reproductive society should be the desired norm.

The UK’s (as of most developed nations’) is an aging population that is gradually seeing the proportion of the older people rising faster than that of younger generations. According to the Office of National Statistics for example, the numbers of the 90-to-99 year olds grew by 12% while that of over-99 year old grew by 36% between 2001 and 2006. This does not auger well considering that the average number of children per a unit family has fallen below two. Much worse, the number of healthy couples facing reproductive problems has steadily risen in spite of the decreasing popularity of single persons opting to get into permanent relationships.

The UK has a lower population growth rate than the European Union’s average. Therefore, the negative attitude proscribed to immigration and immigrants’ baby boom might come as a surprise and belated bonus towards population stabilisation. Coupled with emigrations to warmer countries (like Spain, Portugal and Italy), where taxation and cost of living are less expensive (Bulgaria, Canada and Australia), or for even better career prospects (US, Switzerland and Scandinavian countries), the negative growth might not stabilise any sooner. Much worse, the mortality rate of the younger generations has risen due to crime and substance abuse, which might offset any gains from improved child mortality from better healthcare. As such, the active working population is under pressure to be more productive, thus increasing the pressure exerted on health service providers. A vicious circle emerges that will eventually impinge negatively on the whole bio-socio-economically productive population.

As globalisation has touched the socioeconomic and geopolitical alignments anew, trans-human movements have been particularly heightened. Similarly so, the opening up and more liberalised travel have created new frontiers for people to invade, while tourism has legalised travel to wherever almost anyone wishes to so long as they can meet their costs. Consequently, the human population is a very fluid mass that keeps surging back and forth like a tidal wave.

Population biology

Symptomatic of almost all systems in nature (be they animate or not), populations of all living things follow the sigmoid curve. Therefore, there have been an exponential growth in the number of humans on earth, and progressive migrations have eased of pressure in the high concentration areas. This is likely to continue happening until some external force will step in and check the growth, as has happened in the past for populations of animals and plants that have been threatened with or have become extinct. Populations with higher reproductive potential have greater chances of propagation and success in invading and occupying new habitations. And continued superiority is based on the competitive advantage of the young ones especially with changing environmental condition. For such success to be realised, four stages in the reproductive cycle have to be optimised.

Unless for the lower organisms that reproduce asexually, almost all other organisms reproduce by sexual means between male and female organisms of their species and thus do contribute their genetic makeup to their offspring(s). For that to happen and until another organism is borne, there are some fundamental processes that happen without which and or in case of malfunctions, no new life would be produced. It has only been the colonisation of new frontiers by the emerging superior populations that has led to other life moving in.

Reproduction is inherently the ability of the male and female organisms coming together and meeting some level of fertility requirement. There is no hard-and-dividing line of the fertile and infertile organisms, but a range through sub-fertile, infertility exhibited physiological processes that can eventuality be overcome, secondary infertility that often happens after a period of normal fertility, and the zero fertility status. This article will focus on human reproduction.

Miracle of sexual reproduction

Four biological processes are of great importance in sexual reproduction, termed gametogenesis, fertilisation, gestation, and parturition.

Gametogenesis, or the making of the reproductive cells (ova and sperms) are cell division processes that occur in the reproductive organs (ovaries and testes) of the female and male. The process involves division of each cell into two by a process called meiosis that halves the number of genetic material that is in each cell. Each normal cell contains pairs of genetic material in structures called chromosomes. Humans have 46 chromosomes that contain all the genetic material that determines their form and function; therefore, each cell that is formed in the reproductive organs has 23 chromosomes. These cells undergo development to become sperms in males by developing a tail to make them motile. In females on the other hand, the ova do not change much until one of them is directed by a chemical message to start developing in readiness for maturation and release.

Fertilisation occurs after successful fusion of the male and female reproductive cells (called gametes). Immediately after the sperm (just one) enters into the ovum, the latter’s outer wall undergoes transformations that ensure that no other sperm can penetrate it to introduce another set of male’s genetic material. This process marks successful fertilisation of the ovum (subsequently called zygote or foetus). The zygote has two sets of chromosomes from the sperm and ovum, and these pair up according to their respective numbering and symmetry. The reconstituted cell’s genetic material is the determinant of the offspring from the two parents.

Gestation is the period from effective fertilisation to the time a child is born, and normally lasts nine months. By effective, the reason is that more oft, the resultant zygote is prone to many hazards before it becomes a life. In case of some anomalies, spontaneous abortion of the foetus often ensues soon or later. In other cases, the zygote may embed itself within the fallopian tubes before it gets into the womb and that might lead to termination of the pregnancy. In other cases, the foetus may develop normally but die before full term; and there are many bio-physicochemical causes for such. Or else, some weakness of the cervix might cause the womb not support the presence of a normally developing foetus. The health of the baby is intimately connected with the health of the mother.

Parturition is the process of giving birth to the foetus. From the onset that is marked by labour pains to the time the baby breaths its first, the duration could last from minutes to weeks, and so is subject to many disturbances. Although giving birth is a natural process, many too are the hiccups and especially due to the delicate nature of the mother’s health and the fragility of the baby. Many healthy babies die during birth due to stress to the mother.

Infertility can arise at any one of the four processes, and that makes women more susceptible to higher frequencies of infertility than men considering that all that men need do is to avail healthy and motile gametes.

Female infertility

Generally, women are more reproductively fertile soon after onset of puberty until they turn thirty-five. There then follows a gradual decrease in fertility until menopause. However, there are many factors that affect the fertility of an individual, least of all being hereditary traits and some environmental aberrations. Herein, causes will not be exposed but rather seek to underline the circumstances.

Sexual maturation is initially dependent upon appropriate hormonal balances. The process starts at puberty when the anterior part of the pituitary gland in the brain start secreting the Follicle Stimulating Hormone that, on reception in the ovaries sets in motion the growth and development of an ovum inside a corpus luteum.

The ovaries, too, secrete the two sex steroid hormones- oestrogen and progesterone that are the main conductors of the menstrual cycle. The menstrual cycle has two phases. The first is mainly under the influence of oestrogen and promotes growth of the endometrium to the right thickness and maturity in preparation for pregnancy. The second begins after ovulation and is mainly under the influence of progesterone, which stops the endometrium growing further, matures and stabilises it. If pregnancy does not occur, the levels of oestrogen and progesterone taper off, the endometrium sloughs off, menstrual bleeding occurs and a new cycle begins again every month until interrupted by pregnancy.

Therefore, if a woman’s sex anatomy is normal and her hormones function well, there would be no cause for lack of ovulation and eventual conception, unless other factors deter the normal proceed of the released ovum. This can happen when the fallopian tube is blocked either by pressing body mass or by collection of fluids inside the tubes. Chronic ailments like endometriosis- the failure of inner uterine wall development/thickening with ovulation cycle instead the thickening occurring on the outside of uterus- can cause fallopian tube blockage. Overweight or underweight, too can cause problems with ovulation and conception, just as alcohol and drug use can.

Infertility also occurs when there is a problem with the cervix. Abnormally excessive cervical mucus may prevent the sperm from reaching the egg or make it more challenging for the sperm to penetrate the egg. Age may also contribute to fertility struggles because as a woman gets older, her fertility decreases.

A less realised form of infertility is the inability to nurture a pregnancy to term. Miscarriages can happen when the foetus dies leading to abortion. Pregnant mothers who take too much caffeine expose themselves to miscarriage as caffeine might harm the unborn baby that cannot readily metabolise it. Other behavioural activities like strenuous exercises and overwork can also harm the foetus leading to abortion. In some rare cases, a weak cervix is also unable to support the weight of the uterus and thus cause abortion.

Male infertility

There are few conditions that affect male fertility compared to females’. Hereditary disorders could cause infertility when the chromosomes are affected, or the sperms have poor motility, or the gonads are underdeveloped. Little can be done to change that. However, behavioural factors like early sex exposure and incidences of STIs do affect male fertility. Also, taking long hot baths can also cause premature death of sperms. And, the position of the gonads also makes sperms production a premium, especially for those who work on saddles, or drive for too long, or in case of accidental knocks during cycling and other play activities.

Overcoming infertility

Procreation is a natural process to guarantee the very existence of our very selves, and thus of life itself and the universe as is known. Yet, not all are destined to, and tend to suffer immensely fighting fate. A future constrained of optimal reproduction puts many to depression as hope comes dearth.

Infertility affects approximately one out of every six couples. An infertility diagnosis is given to a couple who is unsuccessful with their attempts to get pregnant over the course of one year. Unfortunately, in-vitro fertilization (IVF), to the rescue has recently suffered a severe blow when the anonymity of male donors has been lifted. With a lifestyle placing lots of blame on absent fathers who suffer double when families break up- itself an almost guaranteed prospect- few would-be donors are eager to be dragged to courts in a distant future to meet costs they did not wish for and only contributed to on humanitarian grounds.

Couples who cannot conceive and bring forth a new life could be going through a myriad of many possibilities and causes. Starting a family at a later age when sexual fertility is lower is a reason for increased cases of reported infertility. As women have become more independent, they have few constraints to forcing them into relationships that would obviously lead to increased activities for conception.

One of the main reasons why IVF doesn’t work is chromosomal abnormality. Full chromosome analysis offers huge hope to many couples who have a poor chance of conceiving, those who have had many failures, and for those who want to maximise their chance at each attempt. In such cases, egg donors would greatly help. The assisted reproductive technology intracytoplasmic sperm injection (ICSI) is being increasingly used in combination with IVF, even for couples who do not have problems with male infertility.

Although career demands have placed a burden on the reproductive patterns of the population, fertility has been a contributing factor too. The usual culprits- drink, drugs, smoking and diet- have been scientifically and socially attributed. However, there still are unexplained cases that comprise 25% of infertility involving the male partner(s) too. When fertility is diagnosed to be male inadequacy, sperm donors become important. And most recent, synthetic sperms have been tried and tested by British scientists, and this might hold greater hope especially where anonymity is required.

Adoption and surrogacy is open although complicated. Similarly, fostering can help. However, many will still be happy and childless. The avenue one takes depends on personal attitude to children and no one need feel left out or challenged over childlessness.