It is more biologically and logically sound of man to have greater sexual attraction over a busty woman.

Americans and Europeans — both men and women — believe that a C cup is the ideal bust size, according to an international survey undertaken by a medical tele consultation website. More generally, men and women prefer bigger cup sizes, namely C, D, and DD.
Over six out of ten women (60.4%) said that their ideal bust size is a C cup, compared with just over one in two men (53.6%). Overall, this mid-sized cup is popular with both men and women, in both Europe and the US. Note, however, that 35.3% of men prefer a D cup, compared with 30.5% of women.
Poland and Hungary differ from other European countries in that they view a B cup as the ideal bust size.
Is this ideal size in sync with reality?
Fortunately, the survey reveals that the British, Belgians and French have an ideal which matches reality, meaning it’s in sync with the average stated bust size.
For the other countries, namely Austria, Germany, Hungary, Italy, the Netherlands, Portugal, Spain and the US, reality falls slightly short of expectations (in most cases, those questioned prefer a C cup, whereas the average stated size is a B). Poland and Romania are the exceptions in that their ideal is a smaller bust size.
This match between the ideal and reality means that most women are satisfied with the size of their bust. In Europe, over eight out of ten women (84.8%) with a C cup say they are happy with what they’ve got. This satisfaction rate is 72% for those with a B cup.
The survey was undertaken in 2016 by www.zavamed.com. A total of 1,000 Americans and 1,000 Europeans — 940 women and 1,060 men — were asked what their ideal bust size would be.

Validity and Soundness
A deductive argument is said to be valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false. Otherwise, a deductive argument is said to be invalid.
A deductive argument is sound if and only if it is both valid, and all of its premises are actually true. Otherwise, a deductive argument is unsound.
According to the definition of a deductive argument (see the Deduction and Induction), the author of a deductive argument always intends that the premises provide the sort of justification for the conclusion whereby if the premises are true, the conclusion is guaranteed to be true as well. Loosely speaking, if the author’s process of reasoning is a good one, if the premises actually do provide this sort of justification for the conclusion, then the argument is valid.

While some women long for bigger breasts, those with overly large breasts may inform them it’s not always a blessing. Abnormally large breasts, also known as macromastia, have been linked to several physical health issues ranging from pain to migraines. 
Popular blogger Monica Froese documented her lifelong struggle with larger breasts in a Healthline article titled “5 Reasons Having Big Boobs Isn’t Everything It’s Cracked Up to Be.” She explained she often had a tough time finding a bra that fit right and her breasts got in the way of playing sports.   
  
Buglino Plastic & Reconstructive Surgery delves into the medical issues that can arise from overly large breasts, and how to treat them. 
 
Neck, Shoulder & Back Pain
Larger breasts have a tendency to pull the shoulders down and hunch the back, leading to poor posture, and ultimately, persistent pain in the neck, shoulder, and back. A study published in The Open Orthopaedics Journal examined more than 300 women and concluded: “Breast-related shoulder-neck pain is thought to result from changes in the centre of gravity, and large or heavy breasts may lead to continuous tension on the middle and lower fibers of the trapezius muscle and on associated muscle groups.”
This is amplified by the fact that women with bigger breasts are often wearing the wrong size bra. A 2013 study of postmenopausal women states, “Increasing breast size and how a bra is worn may have biomechanical implications for the loaded thoracic spine and surrounding musculature.” Larger breasts and increased BMI were concluded to be associated with thoracic pain.
 
Shoulder Grooves
If your breasts are extremely large, your bra may not fully support them—even if you’ve been fitted with the correct size. This can cause your straps to leave deep indentations in your shoulders. They may not disappear once you take your bra off. Purchasing a wide-strap bra can help, but may not eliminate the grooves entirely. 
 
Rashes 
Bigger breasts create the perfect environment for rashes to form beneath them. Your breasts will rub against the skin on your abdomen, causing friction, moisture and heat. A sweat rash known as intertrigo, an infection caused by a yeast condition, will form. It will appear in the skin fold as red or reddish-brown, raw and itchy, cracked, and sore. 
 
Numbness
When bras don’t fit properly, your breasts can become numb. This is a result of the compression of small nerve fibers in the breast tissue or chest wall. Large breasts can also lead to numbness in the hands and fingers if they pull the torso and affect the neck position. This poor posture can lead to compressed nerve pathways down your arms.  
 
Inability to Exercise & Shortness of Breath
The aforementioned woman who documented her problems with her breasts also cited inabilities and concerns about exercising. She felt her breasts bounced too much while working out, so she was embarrassed to go to the gym. Larger breasts also cause shortness of breath, which can be a contributing factor to quitting training. The weight of the excess tissue can constrict the natural movement of the diaphragm. A study published in the journal Plastic and Reconstructive Surgery, shared by the National Library of Medicine, found participants were able to breathe easier following breast reduction surgery.
 
Headaches
Women often cite headaches as a symptom of having extremely large breasts. One study found that patients with macromastia who experienced chronic headaches or migraines can find relief after a breast reduction. Journalist Beth Ford Roth detailed her journey with DD breasts that triggered “blindingly painful headaches” in an article titled “I Got Breast Reduction Surgery For My Migraines,” for online women’s magazine Bustle. Once she underwent a breast reduction, she felt “free.” 
 

What is the "perfect" or "best" boob size?
According to the study, nearly 54% of men and more than 60% of women preferred breasts that were of average size.
It was determined that 35% of men and 31% of women thought that larger breasts were better, while 11% of men and 9% of women thought that smaller breast size was more ideal.